Not sure about specifically gerber but usually the higher the stage the more flavors/textures are incorporated. I have no experience with their puffs, sorry!
I think the stage 2 is pureed just slightly thicker, although to be honest i can hardly tell either. And a lot of them are flavor combos since you've already tried them alone. I havent tried puffs etc, but we did get some of the yogurt melts...he has yet to get one in his mouth yet though so Im not much help!
Re: gerber foods