go straight to the AE92 Corolla front discs, they are a little thicker, a little bigger in diameter and use the same caliper. MASSIVE improvement on 87+ tercels(so if you were gonna use the tercel/paseo discs, get a little better for same cost

as for rear disc's.. you'll have to make up some brackets to hold the calipers... but FX16 rear discs or Starlet GT rear disc set up would probably be your best bet... unless ofcourse you swap out to supra/celica/corolla rear axle anyways
Typically when dealing with 80's toyota brakes on similar chassis don't bother swapping the master cylinder they are usually all the same .. all you need is the residual pressure valve that threads in between the hardline comeing out of the master cyl and the master cyl itself
I know this is true on the 87+ tercels but I don't know for sure on the 4wd wagons