POS = proof of stake. Basically you get free coins for keeping coins in your wallet. More coins you stake, bigger your reward. Not every coin is a PoS coin.
Lots of people will say mining is not worth it.
But let me tell you...last year people were still chanting it's not worth it. But I mined anyway on my 10-year old pc for just 24 hours to see what the results were.
I mined $10 worth of coins at the time. 30-d extrapolation would be $300. My marketing bots made more money so I stopped mining and went back to work as usual.
1 year later I check the wallet, the value quadrupled. $10 became $40. If I mined all month, $300 would become $1200. Not bad for ancient hardware compared to today's performance benchmarks.
My close friend has room full of gpu's.. mined 16+ btc so far this year.
All your other questions..depends how hardware's configured, what you're mining... are you in a pool....etc.