In fact there would be many seats you could possibly use.
Do tell, sir.
Would it be a safe assumption that a newer 78 5 seat configuration could be adapted to a 75?
By 5 seat, the RV spec'd with the "swivel front seat" to access the rear?
(If I've engaged on another, similar question, please excuse)
Same goes for the reverse.
Would it be a safe assumption the a 78 Series swivel seat could be adapted to a 73?
Realize that's a tough one, can't find any info of the "swivel seat" operation, anyway, but verbiage in a 1999 review stated it was a huge improvement in the ingress/egress.
But you need to also check the laws in your area regarding the fitting of extra seats/seat belts.
It's the Wild West here, man.
It's crazy that one can be fined for no seatbelt, which I always wear, while there's but a handful of states with helmet laws.
The other thing is getting a baby in and out of a troopy rear seat doesn't sound like fun.
For me personally, (I bumped an old thread) the only babies I need to concern myself with are 14 and 9.