Do you know when they visit again? I started a new save and made sure to call them cute this time. I got the hearts over their head, but when Ori returned they didn't come with, nor on the next day. (Given that their set gender carried over from my first save, this may be a cross-save bug.)
Edit: It takes a week, give or take. Unrelated to the gender issue, it seems. No idea if it's a repeatable or a one-off.