Are watercolor and gauche usable for doll painting?

I’m not a fan of acrylics and I don’t have any watercolor pencils in the right colors but I do have an extensive collection of nice quality watercolor and watercolor gauche that I could use, but I can’t find info on if that’s ok to use because of how common using watercolor pencils is, has anyone used them before? I’ve tried them on top of the varnish I used as a mascot and they look great but I’m concerned if they’ll survive the final layer of varnish at the end?