When I bought my car, it had been converted to 5 lug using similar stuff to what you are considering.
It had a set of the 99 anniversary wheels (which became standard on 2000 GTs) that fit but did not allow the center cap to go on. The reason was that because the rotors had the bearings, they stuck out too far and the center cap hit the end of the spindle/rotor. I later converted the car over to the Cobra R 4 wheel disc/5 lug conversion and the center caps would then go on (the 93 Cobra R/94-up spindles have the bearings/hub as part of them meaning they stick out less).
The bullitt rims have an even smaller center cap than my old wheels and will probably interfere with the rotor on that setup to the point they may not bolt up. If JStang1124 still has the fox style 5 lug conversion (bearings in rotor), then maybe I'm wrong, but if he has the 94-up conversion, I would think twice about ordering everything.