I've already mentioned I'd like CR with Fai for both Sebastian and Elsa, so I won't repeat it, so: keeping my fingers crossed for a Kurogane for you!
There was a world change event not too long ago involving vampires, so most characters currently present in the game are familiar with CLAMP vampires already, if that's of interest to you to know. Heck, thanks to said event Sebastian is very familiar with the idea of being bound to only drinking the blood of one person.