The Maiden in the artwork and Soh's face.

 Is the Maiden in artwork meant to be ambiguous?

This is Soh's face?

I need to see artwork of Soh's face because Yoshiro is drawn with very feline eyes like Soh, but in-game they're different.

this looks more like Yoshiro

just a little bit rounder.

Yoshiro's eyes and lips are bigger and rounder. Her eyebrows are lighter and lower. Is the art meant to be ambiguous on who the Maiden is?

They obviously bear a striking resemblance because they're related.

They both resemble the Goddess. Another reason to assume the Goddess is an ancestral deity of the Maiden.