Bruno lives inside the walls of his fams house, and he wears green, he can tell the future but his other gift is acting. Overall he's a pretty cool guy.

DID YOU JUST TALK ABOUT BRUNO?

Yes

I mean, the 3 hedgehogs have furs in cool colors. In case you dont know, cool colors is basically a spectrum that goes from green all the way to purple. It excludes the red-yellow spectrum.
But anyway, purple, pink, and blue were taken colors from the hedgehogs. So my best guess is that the missing hedgehog is green, which is also the color of the clothing that Bruno wears in encanto.

Coincidence? I think NOT!

Bruno.