SE, don't overthink Summoner 7.0. Just give people what they want. Just do it.

[ty_taurus]

ah no, considering the current operation of summons. So 1 summon at a time (preferably excluding carbuncle), with their own animation lock. But they can be summoned multiple times during the lego phase, but with an assigned CD so as not to be spammed.

How do you get Bahamut during the opener though? That was what I was initially saying about starting with 3 gems, so that when a fight begins, there's no weird or messy system of trying to get Bahamut out in time. The part about having each summon generate a crystal over its phase, yes. Each has some cooldown so you don't just Titan > Titan > Titan or Titan > Ifrit > Titan, and you can delay Bahamut or Phoenix as needed.