I just casually encountered a glitch where in JPIII, after the family reunion, in the hub world you have to get past a door to get to the "bird cage". As Amanda, I jumped onto the roof of the building, and swapped characters. All the characters followed Amanda and glitched through the door.

However, there is nothing to do there as I do not have the sufficient abilities, and the next level's trigger does not activate. I had to reload my save, which luckily re-positioned me outside of the building, so I could continue as normal.

This does show potential for different glitches elsewhere, although I am not sure where.