IRyS said as much, but Bae confirmed for all intents and purposes, Promise is basically a new gen of existing talents and IRyS will be treated as a genmate of the rest of the girls. Kinda like if Gamers was all pre-existing talents, like Fubuki, and not just a unit like Shiraken or UmiSea. Council is still a thing, but I am guessing it will only be relevant for Anniversaries. Even then, they could probably still celebrate as Promise rather than just Council.