First off, I like how you think out of the box and try to make it possible for new players to get the older event girls (though you forget the Halloween event, even though that event was in a different format :P)

Personally I don't like the idea of the black market and the tickets. Right now it punishes old paying players for having paid for the girls.
And to be honest, you don't want to make paying players feel that they are punished.

However, I wasn't a big fan of the anniversary event. I think everybody has a couple of favourite event girls out there, that they couldn't get, yet it was highly unlikely to get the girl(s) you actually wanted with all of them in there.

I like the event booster tickets though. During an anniversary like event, I'd like it if I could get some kind of booster for a certain event so that when I spin the pachinko, I have a bigger chance on the girls from that event (still RNG, but at least you increase the odds).