AFAIK, you don't need to run Legend calipers in the rear. You will want to use actual Legend rotors in the front though. The 5 lug Prelude rotors are larger, but still about 5mm too thin for the Legend calipers. Just get the Legend rotors, and you should be straight.
Make sure you use suspension components off a base model Prelude. Ask Satan SRV what happens when you use Type SH pieces
Finally, I'm pretty sure all you need are the hub/knuckle assemblies. I'm working on doing this conversion to my 92 4ws in a couple months (once I sell my rims/tires) so keep me posted on how it goes!