The Wj is the model where junkyard swaps stop making sense budget and engineering wise. It gets even worse when you get to the WK and forget about it with the WK2.
the ZJ was the last of the cherokees with backward compatible parts.
i believe you can swap in some steering and brake parts from a WK to an XJ but theres no point going the other way around.
Even the 4.0 engine block on the wj is different than that of the XJs. so picking up a WJ with a blown motor thinking youd have a plethora of motors to choose from, youd be sorely mistaken.
swapping axles into the WJ is a nightmare as the speed sensors are on the axle. to do an axle swap, you need to also swap out to a transfer case with the speed sensor onthe output and reprogram the computer or you will have engine management trouble.