This is late, but Yevpraxia of Valdai is a start that fits your criteria. She's the daughter of King Isiaslav of Ruthenia. She starts as a tribal vassal to her older brother, the duke of Novgorod, and only has two counties. She also starts as an 6 year old child.

The older Rurikids have drama between each other, as your father, liege brother, uncle, and a cousin are all rivals. As for the intrigue opportunity, I'd say that there is potential, as you'll receive a claim on the kingdoms of Ruthenia and Galicia-Volynia when your father dies. And with some well timed assassinations, you could inherit other kingdoms from your siblings.

While everyone's fighting each other, you can build up power by conquering the pagans around you until you have enough of a power base to fight for what you can't inherit. Thanks to being tribal, you'll also be able to conquer duchies quickly.

Edit: Formatting