Getting off-topic, but yes, sometimes these agents can't really have their client's best interests in mind sometimes. The guy that played Clemenza wanted a greater say in his dialogue for Godfather II. They found an easier solution that that: A black armband, a passing comment, and voila! Clemenza is dead, and we get a much more dynamic and interesting character and subplot with Pantangelli. And after that, that actor went on to do.... what, exactly?
On topic, I have seen BTTF several times, BTTF3 twice, but have never seen BTTF2.