The rainbow part is pretty much his "final form" per say so yeah it'll be a single color for when he enters the comic.
Long story short(since it'll be a while before he shows up), Limerick is a copy of Lustrum except this copy became Chrysalis's very own personal assassin/possible lover. Before fully grown Celestia learned of this and thus sent an agent to burn the hatchling beforehand but failed, only burning the left side of his face which explains why he looks like a cruddy troubled past mary sue.
MlpFim/Changelings belong to Hasbro and Fausticorn
Persona belongs to me
Support me please on Patreon/PayPal! please it seems as if I'm making no progress with this and thus family being right about me having to work at freakity Safeway
Also in other news, Remember the Trans guy thing? Yeah not sure if this person is giving up on me plus it seems that I kinda dosed off a little and started giving in or something…idk what's your opinion on this?
Gonna put it in a journal because it's too long
EDIT: Forgot magic shape thing