What Fresh Hell is this? (New owner of very used XJ)
 

Just picked this one up locally and started looking into it.

Lots of play in the steering, previous owner who lifted it says he used an incorrect bolt on a swaybar (narrower and allows visible movement when turning the steering wheel) so I'll probably need help figuring out how to find a replacement. My only Cherokee experience is owning one for a couple of years last century.

Well, start by posting a pic of the front suspension so we can get an idea of the setup. Really, the sway-bar only has a few sets of bolts. Chassis rubber mounts (the larger ones under the radiator), and at the top of the endlink. The endlink has another bolt at the axle-side sway-bar bracket.

I would toss whatever he has and upgrade to a set of JKS Quicker Disconnects. Great kit, I have had mine for a while and they are awesome.

Then check the rest of the steering linkage for play. Check the track-bar bolts and bushings - they can wallow out the axle-mount bolt hole and cause a lot of steering play and death wobble.
Almost 100% it is NOT the steering stabilizer - don't waste money replacing it until you are 100% sure the rest of the components are in good shape.

Also check all the fluid levels and flush them if they are dirty or even remotely suspect (for peace of mind).

Thanks.