Idk what a therian is, i support tho, but would these characters count as fursonas cause they aint human?

Miyaro (top) and Kumaira (bottom)
They're both picrews btw

They can if you want, I have seen people fursuit with humanoid suits (they looked kinda human, but they aren't) but people tend to fursuit with more animalistic cosplays

ah, kay, ty

Again, tho, you could make it into a fursuit!