OK, I take the comment about #3 back. According to the Minkin song history written by Julia Mordaunt, who I must concede is more of an expert on all things Mike than just about anyone, says the backdrops were used at select shows from 1991-4. I misremember them being retired in the spring/summer of 1993, at the time Kuroda first got his signature moving laser lights in addition to typical theatrical "can" floodlights, because the plastic backdrops didn't seem to work well with the Altstar "movers" because of reflections.

So...can anyone who absolutely can and will use the tickets give us the correct answer to #2? Another hint tomorrow if someone can't.