With the disclaimer that I feel that anyone can RP whatever they like if they're having fun: I also think it's super risky to take a canon faction like this - especially before more lore gets released that could potentially mess up all your plans and especially if you're letting folks take last names that link them directly to the house or creating occasional NPCs that are supposed to speak for the house. Personally, I feel that it's probably a safer bet to just create a regular, original noble house that you can do whatever you like with without having to fear of being constrained by what SE might do with the major faction.
