(And before you ask, I haven't drawn my fanon changelings yet)
In my story, "Sunset Eclipsed", the Changelings of the EQG world are a power-armored terrorist group known as the Chrysalis Syndicate, led by Supreme Commander Chrysalis.
Although I think that a more realistic (?) human world counterpart for the Changelings would be the students and faculty of a rival school, with Chrysalis as the principal.
awesome work. I real like how you drew Chrysalis like a goth,
she could be Shining armour's Evil ex who wants to get rid of Cadance.