I can’t help with the rest, but we put a GTR rear end into a mates R32 Gtst and just unbolted the suspension points from the Gtst rear end put them onto the GTR rear end – Thus allowing us to keep his Gtst Buddy Club coilovers.
GTR half shafts are bigger, so would never physically fit/work with a Gtst diff AFAIK.
Wasn’t a hard job, wasn’t really worth the effort – We only did it for the more meaty half shafts