I think the Dwarf pool is a French one. It has been there since the start of the monero. It has not done evil now.

I have some bitcoins. I will hold it for the long term. In the past, the bitcoin price has risen many times.

If you want to mine Ethereum with Windows, you need 4 GB memory and 64 bit operating system. It is quite profitable.

There are a few more Ethereum faucets now. They all give out reasonable amount of payment. It worths trying.

DDR3 is not a problem for mining. You can mine Ethereum coin now if your electricity price is not too high. You need at least 4GB memory and 64bit operating system.

For the off-chain transactions for bitcoin, is that a centralised system? Just like you use visa credit card to process your transactions?

I think it is better not to use online wallet. It is better to control the money yourself. Do not trust other people.

The History of bitcoin is too short to say holding bitcoin a long term is a good way to make money. So far, for every 3 year period, the price always rise.

It is better to read some tutorials before starting mining. http://cryptomining-blog.com/ could be a good source. But just read that after you are little familiar with mining first.

The price will go up or down in short term. We cannot predict that. But we know the price will go up in long term.