Hand 1, calling is my standard here but I'll raise if the limpers are habitual limp/folders. Never never fold. J9s on the BTN in a limped pot, as long as you play well postflop, is a goldmine imo.

Hand 2, so what if it's an attempt to steal the blinds? You folded J9s on the button when it was limped so why think about calling with 35s? Also, this is terribly unlikely to be a steal considering it's a minraise and there's a limper. This is either a pot sweetener/weak isolation raise with a drawing hand or small pair or someone trying to appear weak while still building the pot with a big hand. I like calling here but you're reasoning is poor.

Hand 3, I like a raise, isolating limpers from the button is nearly always +EV. A fold is ok if the blinds are playing loose. Calling can be profitable too depending on how poorly the limper/blinds play postflop.