IMO there will almost definitely be a chain fork of some sort. If BIP 91 activates, it could very well activate with less than 80% hash rate and that can cause a chain fork. Even with 80% there could still be chain forks. If BIP 91 does not activate, then BIP 148 will activate and Bitmain's UAHF will also activate and that will result in chain forks too. I think that there will be chain forks, just that they may not necessarily be persistent and result in two blockchains.

That is expected behavior. Bitcoin Core will generate new private keys (and a new master HD key if HD is enabled) after you turn on encryption since the unencrypted private keys could have been exposed. The new keys will always be encrypted. Your previously used private keys will still be available so you can still spend any coins you had, but any keys generated after enabling encryption will be new to your wallet.

Yes. You can make transactions that send coins back to yourself. This is recommended as if the taint attempt fails, you still control the coins on both chains.

If the chains have cleanly split and there is no risk of one chain wiping out the other chain, then 1 confirmation is enough. However, I recommend that you wait for 6 or more confirmations before continuing.

Yes. You will need to have multiple wallets, one for each chain.

Yes.

If you do not care about your privacy, you can and should send all of the coins in your wallet. It does not matter where you send them, but I recommend that you just send the coins to another address in your wallet. Such transactions are allowed. There is no need to make an entirely new wallet for this.

Yes, Electrum will allow you to choose the chain that you want to use. You can do this by choosing the Electrum server which you connect to.

Yes. You will need two separate wallets and instances of your wallet software.

Running a full node is extremely simple; just download, install, and run Bitcoin Core.

Yes.

I will be writing up detailed instructions for that and either adding it to the Bitcoin.org alert or making a post here with those instructions. I have written the basic idea of the tainting method here: https://bitcointalk.org/index.php?topic=2012799.msg20104865#msg20104865. This method is also automatically done by Bitcoin Core since it will include a locktime of the most recent block when a transaction is created (with some randomness that allows for a locktime to be chosen that is up to 100 block behind). So long as the minority fork is more than 100 blocks behind and the transaction pays a high enough transaction fee, then this method with locktimes will work.

Bitcoin Core is not designed for you to be able to add and remove wallets at will. It is not designed for you to use wallets that are not in the Bitcoin Core datadir.

Besides the fact that Trezor and Ledgers do not work with Bitcoin Core, they also do not do anything with wallet files. Rather a wallet has to support the Trezor and Ledger hardware interaction APIs and send the device whatever data via those APIs.

Move the wallet.dat file from Bitcoin Core's datadir to your USB drive. When you want to use it, move it back to the datadir. Alternatively you can move the entire datadir to the USB drive but this will require your USB drive to have over 120 GB of free space and it will make Bitcoin Core perform much slower.

Blockchain.info used to have some way to export your private keys, but I don't think they have that capability anymore. Either way, if you want to be able to use your Bitcoin on all forks after a chain split, then you need to control your private keys and control which chain you are using. Using a web wallet like blockchain.info will not provide you this capability. The easiest thing to do would be to just get a desktop wallet (preferably a full node wallet like Bitcoin Core) and send your Bitcoin to an address in the desktop wallet. Then you will have full control of your private keys and be able to choose the chain(s) you wish to follow.

You control your private keys. Which chain you want to spend on only depends on the wallet software you use to interact with your hardware wallet. The hardware wallet itself does not know about nor does it care about the blockchain it is signing transactions for.

There is actually an amazingly simple way to "taint" your coins that I have only recently heard about. This method requires using transaction locktimes and may require a bit of advanced skill (most taint methods require that anyways).

To taint your coins, you need to make one transaction that is valid on one chain and invalid on the other. Since a chain split will likely result in one chain with a majority of the hash rate and one chain with a minority of the hash rate. The chain with the minority hash rate will produce blocks at a slower rate so it will be at a lower block height. Thus you can make a transaction which has a locktime of the most recent block on the chain with the majority hash rate. This means that the transaction will be valid and can be mined on the majority hash rate chain, but is invalid on the minority hash rate chain until it's most recent block height matches the locktime that you set. Once your locktimed transaction confirms on the majority hash rate chain, you immediately make a transaction which spends the same inputs but does not have the locktime and get that confirmed on the other chain. This second transaction will be invalid on the majority hash rate chain because it conflicts with one that has already confirmed, and if the transaction confirms on the minority hash rate chain, then your coins will be successfully split. You can then spend from those transactions on their respective chains without any risk of transaction replay as any transactions that spend from those will be invalid on the other chain.

Then that is a problem with their service and users here cannot help you. If their support does not answer you or does not do anything to rectify the problem, there is nothing that users here can help you.

You can most certainly make a large number of transactions with a small amount of Bitcoin. Testnet does not have very high transaction fees and Bitcoin is extremely divisible, so just make a lot of small transactions.

You can also use the Regtest network which is just a private test network. You can mine your own coins on it from the very beginning of the regtest blockchain so you will get 50 regtest coins for each block.

Coins at rest means that the coins are not being transacted. This could be in coins in cold storage or just that you are not making or receiving any transactions. Any coins that are from a transaction that was confirmed before the fork or are sent in a transaction that was confirmed before the fork are fine. However any coins in an unconfirmed transaction during and after the fork may not be.

Likewise if your fees are too small then players won't come to your site since they won't get their money withdrawn quickly.

Do not use fixed fees. That will likely result in your transactions remaining unconfirmed for a long time. When that happens, you will likely also end up spending from those unconfirmed transactions and make long chains of unconfirmed transactions. When that happens, you will end up making it impossible for anyone to actually get their money off of your service since it is all tied up in long chains of unconfirmed transactions.

If you really do not want to use a dynamic fee rate which will almost always has you pay a sufficient fee for your transactions to actually confirm, you can set a fixed fee rate using the settxfee RPC command. This command allows you to set a fee rate in BTC/kB and your transactions will use that fee rate.

Also, to avoid paying a lot in fees and making a lot of transactions spamming up the network, you should batch your transactions. That means that instead of making one transaction for each withdrawal that a person makes, you instead periodically, say, once an hour, make one large transaction with all of the withdrawals that have been made since the last batch transaction. This allows you to reduce the number of long unconfirmed transaction chains, reduce the number of small change outputs that you need to make, and ultimately reduce the transaction fees that you are paying.

No. They aren't even safe to use normally.

There are two lines that you want to change: https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp#L100 and the line after it (101). Change those two lines so that the time is just 0 and that will disable segwit for your build.

Edit: Do this at your own risk. There may be unintended consequences of doing so as 0.13.1+ was designed without any segwit disabling capabilities in mind. You may end up partitioning yourself from nodes that will give you blocks in the non-segwit format.

The transaction fee is not based upon the value that you are transacting, but rather on the size of the transaction in bytes. The size of the transaction in bytes is determined by the number of inputs you are spending and the number of outputs. If you have many small inputs, your transaction will be larger and thus you will be paying a higher transaction fee.

You can choose the transaction fee rate that Bitcoin Core uses from the GUI. Just click the "Choose" button next to the where it says "Transaction Fee" at the bottom of the send window.

If you go into the console tab, you will see a message from the server. This will usually include the user agent of the server you are connected to and that will tell you whether they are Bitcoin Core, UASF, BU, Bitcoin Classic, etc. If you do not see that there, then connect to one until you see a user agent that you like.

The safest thing to do is to use Bitcoin Core as it is a full node and gives you control over which chain you want to use (via the invalidateblock and reconsiderblock RPC commands).

It depends on your wallet software. If you are using Bitcoin Core, then you are fine.

If you don't spend your Bitcoin, no, there is no risk. Bitcoins at rest (i.e. remain unspent) are not at risk.

There are instructions for verifying the release signatures here: https://bitcointalk.org/index.php?topic=1588906.0

AFAIK, there is no write up of how pruning is implemented. You will have to look in the source code for that. Since manual pruning is now available via an RPC command, I would recommend that you start looking there to see what it does to prune: https://github.com/bitcoin/bitcoin/blob/master/src/rpc/blockchain.cpp#L849

No.

Nothing. Many of the Core developers believe that both BIP 148 and Segwit2x will fail. In the event of a chain split, there will be an alert posted on bitcoin.org (there's going to be one anyways because of the possibility of a chain split) with instructions on how to make your node follow the chain you want it to follow. It's very easy to do by using the invalidateblock RPC command.

How did you make your wallet? IIRC that only happens if you create the wallet from imported addresses.

If your wallet is a watching only wallet, then your wallet does not contain any private keys. This means that you won't be able to send transactions or sign anything.

How did you create your wallet?