I think I agree. If Bourbonnais, Orleanais & Co. are French vassals at game start, Kiev could be a Lithuanian vassal in 1444 as well, since the OP provided actual agruments to do just so.+1, more playable nations at the start is always nice and it seems to be historical.
I don't think that either RM or Historical Friends modifiers are needed, this would railroad it a bit much.