If I’d been smart, I woulda done Pluto as a Semi-quad from the start, and have introduced her species as ‘Equaad’ from the planet Equess, as a sort of original species to separate it from pony somewhat.
Well it’s a bit late now. As tempting as it is, I don’t think I’ll suddenly switch to drawing Pluto as a semiquad in future comics. You’ll probably see her in this form a few more times in the future.