Muck cards and min raise

I have had a discussion with a lot of friends recently about texas hold em no limit rules...


If after the river is shown everone checks (no raise) are all players forced to reveil their cards or can they muck if they so choose to?

Also what are the rules for min raise? It starts of from small blind right? And then it remains as the previous raise during the same betting stage right? So say blinds are at $1/$2 and someone raises $10 after the flop, and I want to raise even more, do I need to raise it to $20 or can I raise it to $11?

The last person to bet/raise shows first - even if there were no bets on the river, the last person to bet/raise the turn would be first etc. If a pot is unraised preflop and then checked down I *think* it goes by position, where under the gun shows first and big blind last. If someone shows a hand that beats yours of course you can muck without showing.

A reraise has to be at least the amount of the original raise. Why anyone would want to raise $1 more into a $10 raise anyway I don't know...

as far as i'm aware if there is no raise on the river, the hands are shown down back from the dealer, you can muck your own cards whenever you like when someone bets a raise has to be a minimum of double the bet a re-re raise only has to be the big blind more ( but this is a pointless play)