I've only ever dropped military skydivers but we made sure any protrusions in the cabin were taped over to prevent snagging hazards.
I've had smoke pulled in the aircraft by an over-enthusiastic jumper but fortunately no canopy problems.
As far as the flying goes it is the sudden change in C of G, particularly lateral, as they leave the aircraft that can catch out the unwary.
Long time ago, Scout 10,000 ft (ish) over Netheravon four freefallers. Third jump of the morning "can we all go together" sure say I expecting them to go the way they were sitting eg two either side, facing outwards. They had previously jumped in pairs one each side. simultaneously, what a mistake to make, as they suddenly huddled tightly together in the back and rapidly dispatched themselves in formation out the starboard side. Thin air massive lateral c of g change hmmm ILAFFT!!
Pre jump brief covered everything that could happen except what did. The Queen of the sky's was on my side that morning.