Remember that there are two series of Wranglers. The early Wranglers were the YJs. Those were leaf spring front and rear, with rectangular headlights. The current series of Wranglers, 1997 and newer with round headlights, are coil spring front and rear. These Wranglers are the TJ series.
The front axles from TJ Wranglers will bolt right into XJs, but they are low pinion, straight cut gears. All XJs through 1999 were high pinion with reverse cut gears. Doesn't mean the axles won't interchange -- they will -- but it is a factor to consider.