You should still be able to use the screen, as its the only bit that can usually be salvaged. You could try to find a x-trail nav but these seem to be hit and miss. You could get a new system altogether.
Not sure about phone system. i don't think it will work here, GC350Z installed the phone system into his car but his was a euro spec car, not sure if it would work with a JDM?
Oh and and