I like your thinking, we really need to raise at some point, and i would prefer to pop the turn. there is a chance he will opt to c/c the river with a weak hand, if that is what he is donking. PP, A4, Jx, that kind of thing.
wtr to getting 3-Bet... I dont play on merge, but vs a random dude at stars with these kind of stats, it's unusual to see a b/rr on the turn with a draw. you're getting ~8:1 if he does 3!, so just count your outs and see if you have enough to call. Dont forget that a J, 4, 3 counterfeit some 2-pair hands. i would do the numbers myself but i need some sleep