[piguy24]

Hand 1, there's not much you're can do. I think if anything, you should be happy the CO was a pussy and didn't get more $$ out of you after flopping the 2nd nuts.
Hand 2, you have to bet the turn, and fold to a check-raise unless you know the opponents really well. They don't know that you don't have AQ or KQ and unless they are super-agressive or particularly astute, they won't raise without a Q on the turn. Since you said that the game was very loose-agressive, an opponent could have a flush, straight, straight-flush draw on the flop, or 6-4, which would've been counterfeited on the turn. After that, you can check behind on the river. The more I've played, the more I think checking the turn (vs. betting and folding to a raise) after a scare card hits can cause you to get pushed off hands on the river. As you played it, your opponents could easily think you had AK and I think you should make a crying call.