Very nice job. I just wanted to give you some input on the backdrop. I believe I have the same and years back they were still experimenting on how to hang it. I put my hardboard up first and then attached the backdrop with the rubber cement - around the perimeter and through the middle or so. Went up fine, looked great - nice product however, one year later it developed the bubbles. Not a few but major bubbles everywhere. I ended up taking it all down and I reinstalled it using the 3M spray adhesive on 100% of the area. Years later - no more bubbles. So hanging it from the top should work for you as long as you don't try mounting the bottom also as I think moisture might have a play in the non-mounted areas expanding/ shrinking etc.
Re lights - it looks like you have the "work" lights under control. For effect lights I just used track lighting mounted above the benchwork fascia. Nice that you can add fixtures as needed, point them where you want etc. Each track is on its own dimmer run off a 24 channel light dimmer panel. Didn't buy that - it was free but I believe CSXAl was looking into some 16 channel ones a few years back in the $500 price range. If I had to do it again, I would have used the 2 channel track lights in some areas to be able to highlight certain things different from what the rest of the track is doing. HD sells the fixtures, but the 2 channel tracks were special order and I didn't care to wait.
Everything above my backdrop is flat black so you don't really see any of it. Don't think you want to do that in your situation but you should check out someones layout to see the effect it gives if you haven't already.
Again, nice job - good luck with the rest of the build. I'm sure you have inspired many to get off their duffs and get some work done on their layouts - I know you have for me. JP