The main branch of the Kurita-Davions was wiped out by Amaris (the Kurita family members on Terra used as hostages? that was them). And the lesser branches were wiped out in the First Succession War IIRC.
Checking the family tree in the back of the old House Kurita sourcebook, Soto Kurita and Mary Davion had three sons.
Vincent died in combat in 2788 but had two sons. The elder, Drago, and his family were all murdered by Amaris in 2780. The younger, Hiragi, died in an accident in 2750 - jumpjet failure.
The next son, Quentin, died in 2800 in a dropship explosion. His only known child, Thomas, committed suicide. Reading between the lines, he may have been the Kurita commander humiliated by the AFFS guerillas on New Rhodes in 2788. Then again, there's an 8 year gap between that and his death so possibly there was another failure on New Rhodes.
The last son, Chada, was the last known survivor of the Kurita-Davions and died in 2810 at the age of 104. (Kurita lifespans are OP). There's literally no information I'm aware of about him save for the above facts. He had no reported children.
It's entirely possible that Quentin and Chada were targets for MIIO in the organisation's early days. They'd have been clear threats to Paul Davion so eliminating them would have been desirable.
