Proper kusari civil war. exiles make a play to retake kusari and re-install an emperor. Loyalist supporting factions fight republican factions.
thats all i got. feel free to expand from there.
Edit: As Knjaz said, the only really active house is the one with the newbie starting system. perhaps have newbies start in kusari instead.
4.87. Also OP a lot of data you have in your post is actually wrong or out of date. Or otherwise eskewed. I appreciate your concern about my house but you have the wrong idea's
Im not sure if you are talking to me or the OP.
4.87 bit was aimed at you. The rest at OP. Anyway I updated my post a bit with a lot more info on how it is seen by someone who has RPed all sides in Kusari. (I do not feel the OP has a great grasp of the Lore of Kusari)
edit 2: as for starting system. have it be a neutral system with 4 one sided jump holes. That head either to NT, NB, NL or NY.