I love the idea of mutants representing different factions on the island. Not that the island is divided but there definitely needs to be representation for different groups of mutants, for example to younger mutants, Dani would be such a good fit to advocate for them. The quiet council is filled with too many older mutants, they need a fresh perspective. My first initial thought to fill the seats were older wiser mutants like Selene, Forever Man, Santa Claus, etc. but with the way the quiet council is structured now they pay more attention to the grander scheme of things rather than what's actually happening on the island. That's why mutants representing different factions would work out very well.
Factions could range from:
Elementals
Aquatics
Ferals
Airborns
Arraki
Youngsters
Non-Human Mutants
Those are just examples but give a feel of what I mean. I don't want the council to be huge so not all the groups obviously but like you get the just.