Question regarding the way Volkswagen have implemented and are delivering their MQB based architecture for all the vehicles.

I know that there are some certain fixed elements with each variant of vehicle like engine mounting points, the firewall-to-dash space, mounts and fittings and there enables a general amount of variability in width, track and such but what of other internal mounted hard points like seats?

Could theoretically if I really like the seats of a GTI Polo and I can find a good set from a wrecker, are they interchangeable with a Mk7 Golf due to the way the hardpoints are fitted in the chassis? Even a B8 Passat?