Yes it will definitely fit since it is the same motor in the 89. The Z31 model was from 1984 to 1989. The Z32 model (2nd gen 300zx) was from 1990 to 1996. (barbie car commercial)
Yes, but you will need a starter shim (unless you're also installing an NA clutch and flywheel on a TT motor) and you most likely will have to clearance the bell housing to fit the TT flywheel. Note this is for 1990-2000, not the older generation.
1985 - 1988 Nissan Maxima is the only other Nissan model with power window motors that will fit a 1986 300ZX.
A 1990 Toyota Corolla.
a 1990 triton motor
Simply put Yes.
Yes it will fit.
it will fit properly if you sawp out the headlights and front bumper from a 87-89