So had this scenario pop up in my local 1-2 game and wasn't 100% if I should be raising preflop, where to draw the line in general.

*Unknown older guy limps in MP and I have seen him open limp AA in the HJ before. Not much more info on him, other than prob loose passive 80bb

*another older guy limps HJ and he is limping like K5o, 63o, super wide. 30bb

*Another old guy limps CO, and prob has things like Axo, 75o, Qxs, Jxs in range. 75bb

Hero on Button w ATo

Basically, I have 3 generic questions.
1) When these guys are playing such weak hands, and prob more on the passive side, how low can we go from the button? I imagine we will get a fair amount of preflop folds if we open to 8-10x preflop and also open up a fair amount of profitable postflop HU situations. I still feel like ATo is marginal, and I think QJo, and KJo are in a similar category. Maybe bottom of range in general is around AJo, KQo, and then JTs+?

2) Default without a good feel on tendencies and range width, what would the bottom of range be from button w 3 limpers ahead, purely on paper look like? AJo, KQo, and then JTs+?

3) how wide can we limp behind 3 players? As more players enter the pot, we need to be more selective with hands that we take to the flop because alot of the time we wont be able to bluff at the pot, so we actually need to make a hand. So w 3 ahead, I guess we could limp behind things like QJo, KJo, maybe JTo, and then fold QTo and KTo. (not confident, but limping ATo still might be good as we can play position and value bet 1-3 streets against weak players)