So as the game states on several occasions, Manju cookie is a buttershell fox. His general cookie lore also shows hints of being a japanese kitsune, as in the folklore creature not just the word fox.
So starting the yap session, we know that a Buttershell fox is implied to be a species or "breed" of fox, as the character of buttershell fox cookie exists and she is named after the species.
Buttershell fox is a much brighter yellow with white, while manju appears to be a cream color. My personal idea or theory behind this is that buttershell fox is the equivalent of saying red fox, it is a specific KIND of fox, not the entire species. [I'd imagine different flavor foxes exist to match other irl foxes]
But then comes the question of why Manju is visibly different from buttershell fox cookie.
Now comes another point, red fox is a bit of a deceiving name! Red foxes can be multiple other colors including black, white, cream, sandy yellow, brown etc.
If i had to use my theory/comparison of buttershell fox being equivalent to a red fox, i can assume and guess that sandy is where Manju would be closest to. If i had to guess, manjus subspecied would be called a Kurimanju coat type as that is his flavor.
Manju does take some aspects of other fox species, his coat seems to be thicker alongside his big chubby tail, it reminds me of arctic foxes. His ears are longer than that of your average fox which seems to aligh with Fennec foxes, though it seems buttershells naturally have those long ears.
"But you said he is a kitsune, does that play into this?"
Well kitsune are yokai, and in terms of folklore you can semi compare them to kumiho, magic fox creatures who can shapeshift into humans. If we take that, we now know manju can turn into a fox if he so wished to.
What is our takeaway from this?
Draw manju as a fox and stan manjuwolf.