As in his base model colour, not his form.
As in his base model colour, not his form.
AFAIK, Hati's color depends on the coloring of your other pet. He'll try and match-ish.
Just throwing out ideas, but did you try dismissing and resummon to see if that triggered the new colour when changing the weapon?
Or perhaps you could tame a wolf with a similar look with the colour you want and essence swap it? I'm assuming that's what you mean by waiting a few levels though.
Dark Blue Hati is the hidden appearance you buy for gold from the ENG person in Dalaran.