all you will need is just the axle. your stock drive shaft will work fine.
but you will also need a rear axle with matching gear ratio. the one from the xj should work, i believe the spring mounts are the same.

but check that xj axle. some had a front center axle disconnect, some didn't. your yj probably came factory with a CAD, but if you get the chance to swap it out with a non CAD axle, then that's even better. but otherwise, hope the CAD on the xj axle is working properly. if not, there are ways to permanently lock it.

 

The front axle in a YJ has leaf springs and an XJ has coils so to swap you will either have to take the gears and carrier out of the XJ axle and put it in you YJ Dana 30 or cut the old brackets off of the XJ axle and weld leaf spring perches on. The XJ and YJ rear are both leaf sprung axles but I am not sure if the spring perches are the same width.

 

oops yep. guess my brain was dragging. lol yeah, leaf springs. lots of unnecessary work.