I used the clutch/pressure plate from the 95.
This may help clarify things:
The input bearing retainer on the external slave cylinder style transmissions has a "nose" upon which the throwout bearing and fork ride on. This should be the same parts (clutch, pressure plate, throwout bearing, fork, pivot ball, spring clip) for 94-00 and maybe even for the NV3500 (the newer 5 speed from 00-04). The input bearing retainer on the internal slave cylinder style tranny does not have the "nose". The throwout bearing and integrated fork are actually clipped to the input bearing retainer.
In your situation, you will need to use all your original components (input bearing retainer, bellhousing. clutch, pressure plate, throwout bearing, fork, spring clip, pivot ball) from the 95, and the tranny and pilot bearing from the 91. So the ONLY parts you should need would be the 91 tranny and a new pilot bearing. However, depending on how many miles your clutch has on it, it may be a good idea to replace it. For you this is simple. For those of us who swap from internal to external, we need all the external parts, which can get expensive.
92 YJ, 4.0L, 5-speed, 35" Goodyear MTR's