
Delightful |

No one related to the vanished house exists any longer. Unless you mean for that to be a plot point? Come to think of it, it would be kinda interesting if someone didn't disappear during the Vanishing. "Whoops, guess you were adopted."
I know the main family's gone, but I figured it would make sense that were a bunch of lesser houses in the Rostland that were once bannerman and knights for the Rogarvias that were still around, right.

Inneliese |

House Rogarvia controlled the lands closest to the free city of Restov, home of the Swordlords. Given that the Swordlords appear to be mostly (if not entirely) landed nobility, it's likely that they collectively control most of the lands held by House Rogarvia as minor barons and such, maintaining both a townhouse in Restov and a small manor central central to their land holdings.
Honestly though, I don't know why Kingmaker gave no attention at all to the feudal system, especially since one hex at the Kingmaker scale is about equal to the land historically controlled by an average English baron.

JohnB |

I worked on the basis that everyone of Rogavarian blood disappeared. Some of them would have left wives, husbands and adopted children around. This lead to:
Rogarvian Spouse: Very little of House Rogavaria survives - just the wives (and a few husbands) who married into the house, and children ‘of the blood’ all disappeared along with the rest of the blood relatives. Now they are fighting for their very survival. This trait is only open to female characters who do not have a martial class. Factional Trait: Special - You gain a +1 trait bonus on Knowledge: Nobility checks, and Knowledge: Nobility is always treated as a class skill for you. Your family motto is "With Sword and Flame."
barony level nobles for Brevoy would be an awful lot of work, and leave less flexibility for DMs. However, I am implementing something of that sort in my game.

Delightful |

I worked on the basis that everyone of Rogavarian blood disappeared. Some of them would have left wives, husbands and adopted children around. This lead to:
Rogarvian Spouse: Very little of House Rogavaria survives - just the wives (and a few husbands) who married into the house, and children ‘of the blood’ all disappeared along with the rest of the blood relatives. Now they are fighting for their very survival. This trait is only open to female characters who do not have a martial class. Factional Trait: Special - You gain a +1 trait bonus on Knowledge: Nobility checks, and Knowledge: Nobility is always treated as a class skill for you. Your family motto is "With Sword and Flame."
barony level nobles for Brevoy would be an awful lot of work, and leave less flexibility for DMs. However, I am implementing something of that sort in my game.
Oh I like this a lot, JohnB. Thanks!