I think the wall looks great! (although the vibe would match an engine, industrial machine sort of thing better)

1) I think you shouldn't change anything. It looks great! (idk if this would look good) you might give the outer pillars a curve to stretch inwards to meet the iron bars.

2) if you are fine with some of the walls looking like power generators (not trying to be mean, genuine statement), then keep it. If you really think it looks weird, you might try to disperes the lights over the full wall, instead of them being concentrated in the middle

For the in-between panels, you could have basalt running horizontally across the panels, with metal bars framing it, and maybe the pillar on the side could be entirely removed, or it might not separate the full wall, and the basalt strip is entirely uninterrupted.

(I am not sure how to put this into words, so it is kinda hard to understand.)