Advice regarding rear seating

I am currently looking for a vivaro and will need seating in the rear, the kids have requested comfy reclining seats (ie one each not a bench seat) and I don't want to fit the seatbelts to the van (so the seats can be moved) I was looking at maybe seats from a convertible or ones with built in seatbelts, fitted to Unwin rails?

Has anybody done this to their van or can point me in the right direction.

Thanks in advance