Since I started this topic, I think I should weigh in with my thoughts...
Frances Fisher as Grayson is an interesting idea, although I really can't imagine anyone being able to capture Grayson's persona.
The big question is who would Gothick pick to play Grayson.
For Lara Parker, I would cast Michelle Pfeiffer. I think she'd make an excellent Angelique, too.
For Jonathan Frid, I pick Sam Waterston. JF has an "old world gentleman" quality about him, and I think SW would be able to capture that.
Regards,
John