2 pair is a pair down, more vc hitting him on the flop he becomes a monster , the more the pair is a pair of 2 rui u will only have two out, and nothing else ! often the move is call in pre flop and the right not nothing then and fold !
I think it depends on how comfortable you are with post flop play in addition to your position. With that said, pretty much any time you know for sure you can see the flop for cheap is worth going for it and pretty much shooting for a set and dumping when you miss unless you feel you can comfortable navigate the post flop streets with just a small pair
No when you have pair in your hands you always have to pay the blinds to see the flop you don't know if you can make a three of a kind or full , I always pay the pair of 2 because it always appears to me at the flop and I always win with that hand , any pair is good to see the flop remember that