Support characters not being able to finish off enemies has been reported a few times, probably already on the list of things to fix.
As for some characters having paperdolls missing (Ami, Molly and Lucille) that’s because they haven’t received their updated paperdolls. (The updated paperdolls are a larger, nearly full-body image and they also have a funky spotted pattern as a background)
It will be fixed eventually. But new content takes priority, or people start getting antsy.