'91 Ram Van rear seats needed

I just purchased a '91 Ram 350 for my mobile SkiSpa tuning van. It has no rear Seating currently and I would like to put in two bucket seats (that swivel?) or a bench seat (preferably with center console). The seating is a must have and safety is number one priority as its for my kiddos. So I would prefer it to fit within the original mounting brackets.

Any Dodge seating experts out there. Is the mounting system/pattern I have in the '91 the same as later models? Can I order two aftermarket buckets for this easily? Or a bench? Will seats from newer models fit without needing a machinist to help retro fit them?

Customizing the van for a ski tuning bench/camper to chase the ski racers around at events. Of course I'm doing this on a budget. Any help or advice is welcomed.