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First one I would call and just c/c turn. Unlikely that he's going anywhere in this hand, and top pair is solid enough against a maniac.
Preflop I don't hate the limp because of the villains stats. He's unlikely to raise this up preflop, and you can pretty much play profitable fit-or-fold on the flop.

Second one is absolutely horrible in every way imaginable.
You have a hand that plays very well multi-way IP, but you choose to isolate... with 3 limpers... at 10NL! Your bet is WAY too small to isolate, so all you're doing is bloating the pot - they're absolutely correct to call with whatever they limped with.
On the flop you get perfect odds to call, but you semi-bluff... 1/2 pot! It's 4-way so it's pretty damn likely somebody has a hand they can call you with getting 3:1... so again. All you're doing is bloating the pot when you're most likely behind.