Difficult. I think the Rïksamblé would allow these princesses to marry Monic nobles. However, you can have Azsrid Genoveva (born 1958); she'd lose her dynastic rights, of course.
Mongols can't into Lecland without Filimon ports.
I give up. Guillem only wanted a pretty Nevan maiden. And no, the Order isn't what he wanted.