Non-binary mc's can date Trouble, Tallys, Chase, Red, Alya and Briony, since they are bi or pan (can't remember rn) (Briony and Lavinet only appear on the alpha demo on the patreon, that have a lot more chapters than the public one.)
All of the ro's have fixed sexualities, so only female mc's can romance Blade (since he's straight) and Shery (lesbian), and only male mc's can romance Riel (gay) and Lavinet (straight).