I'm happy to report that I haven't had any problems with my figures. They're all posing on their stands, with their respective props nearby or in-hand.
Kermit leans slightly forward, but not in a defective kind of way. To me, it just looks like Kermit looks. His head always kind of stuck out further than his body, giving him a slightly hunched/slouched look, probably because of the way Henson had to hold him to perform him.
Basically, I'm saying Kermit never HAS been an upright individual, in the literal sense. I wonder how many complaints are just a result of the way Kermit SHOULD look...