A lightweight wallet connects to a full node and asks from that node for information related to itself. It essentially gives that node a list of its addresses and asks that the full node only relay transactions which pertain to those addresses. The private keys themselves are still stored within the wallet and are not exposed to the full nodes that it connects to. In exchange for the convenience of not having the entire blockchain, you lose some privacy and security as you have to trust that the full node is providing the correct data.

It's likely that there originally were transactions to your wallet but they were unconfirmed and were eventually dropped by the network. Your wallet still remembers them though which is why it displays them to you. The question mark next to them indicates that the wallet is confused about those transactions since they are there locally but not in the blockchain.

No. If you forgot your password, then you can't do anything with the wallet.

Click the Receive Bitcoin button and you will get an address you can use. Your wallet does not just have one address, you will get a new address every time you click Receive Bitcoin.

Get a Bitcoin address from alphabay and then send to that address. There is nothing in Bitcoin for "deposit at service X". No decent wallet is going to have any such specific option.

If the transactions are not particularly important, then pretty much.

Transaction 1 spends from the confirmed transaction. The way that Bitcoin works is that outputs must be spent completely, so transaction 1 spends your output from the confirmed transaction and produces a change output which is what transaction 2 spends from.

It should be "returned" in a few days. However this does not mean that it will disappear from your wallet.

This transaction has confirmed.

This transaction is unconfirmed. Lets call it transaction #1. It pays an extremely low transaction fee, only 6 sat/byte whereas the recommended transaction fee is 360 sat/byte.

This transaction is also unconfirmed. Lets call it transaction #2. It pays a fairly low transaction fee, only 166 sat/byte. However, it also spends from transaction #1, so it cannot confirm until transaction #1 confirms too.

This transaction is also unconfirmed. Lets call it transaction #3. It pays a low fee, only 222 sat/byte. However, it also spends from transaction #2 so it cannot confirm until transaction #2 confirms too.

If you are using an old version of Multibit, it is very likely that your transactions paid an insufficient transaction fee. Since you also sent transactions from an unconfirmed transaction, those other transactions cannot confirm until the first one confirms as well.

Please post the txids of the transactions so that we can see what is actually wrong.

Your first transaction has confirmed.

Your second transaction spends from this unconfirmed transaction: https://blockchain.info/tx/72b2bf6117119e10b50b57a412e68111c8bdd5bc6651e68e694862ec1b7d37b1. That transaction spends from this other unconfirmed transaction: https://blockchain.info/tx/2e8b79e9e7d8035da432c4847983b61874bab334ecd6a2fd5c4ecc72ee3ad980. Your transaction cannot confirm until both of these confirm too.

You have inbound connections, your node is reachable. Bitnodes is not guaranteed to always work. If their crawler is unable to reach you, that does not necessarily mean that you are not reachable. Curl won't work since the node will not send you any data unless you first send the version message.

What RPC command are you using to make the transaction? Can you post the full output of the error for the RPC command? There should be something in there that gives the reason.

I tried rebroadcasting it again but ViaBTC says that the transaction cannot be found. I don't know why they say that, but there's really nothing that can be done about it.

Yes. You do not need to be online to receive Bitcoin. So long as your transactions have confirmed, then it will work.

Armory's QR code and backup stuff is completely unrelated to any other wallet and is Armory specific.

It should be fairly straightforward. Follow the instructions I gave to get the private keys. Then you should download and install Electrum and sweep those private keys into your new Electrum wallet.

Node's don't help with unconfirmed transactions. Only mining blocks can. Blocks are produced at basically a fixed rate (every 10 min on average), so adding more mining hardware is not going to help since the difficulty will just adjust to increased hashrate.

The only thing you can do to help is to support a capacity increase proposal (e.g. Segwit) and hope that it gets activated soon.

If you have another computer that has the disk space and requisite OS, you can move your Armory wallet there and be able to use it there. If you do that, I recommend that you upgrade Armory to the latest version, 0.96 (or 0.95.1 for Mac).

Otherwise, you should be able to export the private keys from Armory and sweep/import them into another wallet like Electrum in order to access your Bitcoin. To export the private keys, open the wallet properties and choose Backup This Wallet. Chose the Export Key Lists option and enter your password. In the dialog that appears, uncheck everything except for Private Key (Plain Base58) and check the box at the bottom which says Omit Spaces in Key Data. The list that is in the box is list of private keys for your address. They should all begin with a "5" and be 51 characters long. You can then take those to another wallet to import.

What is a "good impact"? Just running a node helps the network since it is verifying all blocks and transactions and relaying them.

Use the latest version of Bitcoin Core. You can use the -dbcache option to give the software more RAM so it will run faster.

Armory will not function without Bitcoin Core running and synced. It is an absolute requirement to have Bitcoin Core installed, running, and synced in order for Armory to even work. If you cannot install Bitcoin Core and download the entire blockchain, then you cannot use Armory.

Please do not refer to Bitcoin amounts by their USD value. The exchange rate constantly fluctuates so it won't remain the same value for a long time. That is probably what happened here. The exchange rate at one time (and with one rate) was a certain value, and when you checked the transaction later, the exchange rate had changed. Furthermore, Coinbase and blockchain.info use different exchange rates, so what is $100 according to Coinbase will probably be different from $100 according to blockchain.info

Blockchain.info cannot charge you or take any money away from you unless they control the private keys which sent the transaction, and they don't since Coinbase controls them.