I think you hit the nail on the head here when you said you shouldve 3 bet the flop and lead the turn. I dont like the idea of just calling the flop and going for the turn checkraise in this spot specifically becuz the MP2 guy is the last to act, meaning you now give him the chance to take a free card on the turn if he wants too. I know that given this action he is very unlikely to take that free card, but in general when you are out of position with a strong hand you should tend to take the 3 bet/lead turn line more often than wait for the turn since that way you never give your opponent the chance to take a free card and plus you get more money in the pot right away when you likely have the best hand. Once the BB coldcalls MP2's flop raise you should be more inclined to 3 bet/lead since you now have two donators in the hand and another point thats important is once the BB Coldcalls the flop raise, the odds of MP2 taking a free card on the turn if checked to does go up. Think about it, If MP2 had AK or AQ he would be a fool to bet the turn at this point. I think you should use the call flop/checkraise turn line more often in heads up situation than in 3 handed pots, since people are less likely to take a free turn heads up and if they do it isnt as costly. I guess my main point is since MP2 is last to act, him raising the flop still does not define his hand well enough for you to assume he will bet the turn, so i think its best that you take control of this hand right away with the 3bet/lead line.