If you used a ton of grease on it during the rebuild it is possible that you hydrolocked the hex in the socket. The fact that the hex fits the socket now without issue would also support that. If it was side loaded it may have wedged in there too. You’d probably see a witness mark in the socket from where the bar got stuck though. With a hydrolock there’d be nothing to see.
It looks like you’ve got poly LCA bushings, so the arm sliding back off the pin is normal once you loosened or removed the strut rod. You can do the same exact thing with a rubber bushing, despite misconceptions some people have the rubber bushing doesn’t hold your control arm on.
Regardless of the bushing type the LCA is located by the strut rod, not the bushing. It’s literally why the strut rod is there, to keep the LCA from moving around under braking or to a lesser extent acceleration. It’s why other makes call them brake reaction rods.
As far as putting it back together, if it’s a poly bushing the bushing is probably fine, they’re much tougher than rubber. I’d be more worried about all the beating and pulling on the control arm and torsion bar. Did you hit the torsion bar adjusting lever? Or was that paint knocked off from the lever hitting the frame? If it was the latter that could have been the source of the wedge on the bar.
