Pool mining - personal Hashrate vs. Total Pool hashrate

I'm relatively new to the crypto world. Been testing and using different things, just seeing how they all work. I've run across a few posts here and elsewhere where they are discussing various pools and the best places to mine XXXXcoin, etc. Several details are mentioned, as if they have a big impact on personal profitability. I don't understand these, so I assume other newer members of the community might have the same questions. So I'm posting my questions here, so I can learn and hopefully help other newbies.

1. Pool fees - How are these calculated? Is it they subtract the fee when they transfer it to you? Do they "steal" hashes to cover their fees (like claymore miner does)?

2. Total Hashrate - If I mine at 200 h/s (whatever metric applies to that crypto), I assume the income would be the same at ANY pool. Are the different total pool hashrates affecting my personal income, and if so, how?

3. Number of active miners - If I have a pool with 50 miners, and another pool with 895 miners, how does this affect my mining and profit results?

4. If its the same blockchain (or whatever) for a single coin, but multiple pools, how do they keep everyone from accidentally mining the same block at the same time? Or does EVERY pool mine the same block and the results distributed according to amount of work per pool and then per miner by each pool?

Here is what I think, knowing I am probably totally WRONG. So please correct my errors. I'm guessing total pool hashrate affects how QUICKLY I get my profits. But, the more miners, the smaller that profit will be. So I am thinking I would want a smaller pool so I get a larger chuck, even if it takes longer to get it. But the discussions I see seem to look at it differently. As to the other questions, I have no clue.

Thanks in advance for everyone's help in educating me and explaining all this.

Mike