I'm curious. We had three kinds of insidie, right?

There were Lif's insidie. They're basically his core follower population.

There's Vestec's insidie. They're in the changing plains.

Are Vulamera's insidie still around? I'm not sure if they've been plonked anywhere canon-wise. Maybe they should inhabit the islands. It would explain where they've been all this time.