I know that the rotors are 10 inch for the 86 and 11 inch for the 87. They both use a 60 mm caliper. Are they the same thing? Will an 87 caliper work on an 86 and vice versa?
No, they are not the same. If you want to run '87-'93 5.0 brakes you need to have '87-'93 5.0 spindles. The '87-'93 2.3 uses the same brakes as a Pre-'87 5.0.
Everything is different between the two, different calipers, rotors, lines, bearings, seals, struts. The only part they share alike is the outer wheel bearing. You can use pre-87 struts with the '87-'93 5.0 spindle, but it requires using shims on both sides of the spindle to do so.