[Bartholow]

On 3rd with 3 callers and a dead Q, I might often not bother raising. This is covered in 7CSFAP. But raising can't be too wrong.

4th through 6th all look good to me. If you fold every time someone catches an ace and bets you are giving up too much IMHO.

River is a definite raise. He could have a flush but he could have a lot of payoff hands. I wouldn't even fold to a 3-bet, limit stud is not about making those kinds of laydowns generally.