The BB is a 23/7 that likes donk bets.
Call. A backdoor flush + a gutshot draw are 2+4 = 6 outs, and the Ace can be good. Even you can be ahead if the villain is donking with 2 clubs or JT.
Totally agree, call.
Call or raise, depending on the villain's profile. If the fold raises, raise. If he 2 barrels a lot, you can also raise the turn. If he donks many times but gives up on the turn when called on the flop, then call.
Call. He can also be betting two pair or a set because of the scary board (to avoid giving you a free card). Call is better than raising.