[dreed]

first to answer the 3 bet preflop question? Why 3 bet it from out of position against 3 opps. The villain may not have much but I can see one of the callers with AJ or AQ.
Second leading the flop against the villian would be an ok play heads up but a check raise is better, but leading with second pair into 3 opps is not +EV. Let the lag player keep the lead and see what the other 2 opps do. When they fold check raise the flop and bet the turn. As for him 3 betting the flop how often does he 3 bet flops when check raised. That would give you a clearer answer how to proceed if he 3 bets. Defenitly not going to fold to it. I may bet out on turn and see how he reacts. If he raises and I miss its time to let it go.