>>713164554
Toby is obviously leaving the door as wide open as possible because of fandom autismbux but I don't think any of the characters are meant to be nonbinary, only ambiguous/unknown.
I can't speak for Deltarune but before and around the release of Undertale Toby made several comments and tweets where he referred to "the kid" (Frisk) using male pronouns, and IIRC one of the official Undertale artbooks also called Napstablook 'him' which caused some outrage and was "corrected" in a later revision.