zmjeeps.com has the leaf spring and LCA bolts. You want at least 10.9 hardness for those, preferably flange head, if you get them through mcmaster.
However, I would simply pull LCA bolts out of a WJ. Same diameter, strength, and thread pitch, and you can find them new enough that the bolts are still pretty damn clean. Some of them have stupid flag nuts, but they take the same nuts the stock XJ LCA and leaf bolts do.
If you need part numbers to get them from zmjeeps I can look them up for you pretty easily.