I wouldn't even try to do two jams at once. Honestly, with work and everything else I felt super swamped with just one limited scope jam game, and I was putting other stuff aside to work on it.
I think through that lens a lot of the issues make sense. I can see how things would get left by the wayside or done the fastest possible way with a looming deadline approaching. The battle system worked out well; despite the last-minute shift it didn't feel confused, it was balanced and satisfying. The other party members being thrown in last minute explains why they're so thin.