I plan to matrilineally marry a Sayyid character to some daughter to get that trait into my dynasty (because I can ), but how likely is it I will succeed? Right now, from raiding, I (a Norse/Norse blob) have two Sayyid boys in my prison: an 11-year-old Norse/Sunni Hashimid (hope he's still going to convert - the educator is zealous, damn it...) and a 6-year-old Norse/Norse Umayyad (he was born in captivity

). Now, while I have these boys in prison, I am not their liege, so that's a bit of a problem.
1. How does "must not marry an infidel" work on prisoners who are not of the same religion as their liege?
2. What happens if I fully annex the liege of one of these prisoners? The Umayyad Sultan of Mauritania in particular is on his last legs, and his... grandson, in fact, is my culture, my religion and my prisoner. Will he become my courtier or a landed Umayyad's courtier or some random Norse guy's courtier?
3. In case of the latter, can I even invite claimaints (because if I don't kill that boy's grandfather and father, there will be "no reason to move" :glare

if I already control the territory he has claims on? Will giving independance help here?
I can probably manage electing my 4-year-old daughter (only Quick one that hasn't died yet

), but I'd rather not have the regency (my Fylkir is 69 already, he's gonna die soon) if there's no way the plan is going to work...