When my Jeep had aluminum angle shims it would make loud popping and cracking sounds. Several people asked me if something had snapped but it was "normal" for my Jeep at the time. When I put in steel shims, the noises went away. In your case, if the springs are stock, you might still get noises if the u-bolts for the leaf springs are not torqued right. Just something to check anyway.
When I changed my suspension, the U bolts would cause a popping noise when making tight turns, and they would get worse with rain, so it sounds similar to what you describe... Check the torque, as they can loosen up after a suspension change (or if they have been removed for any reason). Also check the leaf spring bushings just in case (both the one on the spring and the shackle).
As for the rear track bar, you can remove it without any handling worries. JFYI, CJ's did not have ANY trackbars (front or rear, IIRC), and most lift kits (as was the case in my RE 4" lift), instruct you to completely remove the rear trackbar. Many people in this forum actually drive on a daily basis with no rear OR front track bar (I myself use a telescopic track bar on the front, just because I prefer to do so).
