I haven't tried that path myself, but I believe if you choose to conquer Tabnath, a doll appears somewhere in it at some point afterward. Stick the collar on the doll and the knightess will inhabit it as a new body.
I think someone recently mentioned the weird thing about Wind and Yterre's chateau, so there's that.
Initiative was already Jyla's marriage bonus... Come to think of it, its new effect (the user can act twice on the first turn of battle, unless the enemy has preemptive actions) is actually very useful for Lilina. She can cast two buff or shield spells on the first turn this way. Also now I don't have to pump Wind's Attraction up just to see what Lilina gets from her, so yay. Though I have commitment issues so I'll probably just end up not having her marry at all in this playthrough...