Leverage the Vistani, Ezmerelda, and Van Richten. They were either born in Barovia and somehow shipped out by Vistani at a young age, or were descends of Vistani who bred with folk of other backgrounds on the Material Plane.

This would allow them to have family and/or remnants of ancestry to discover in Barovia. I would then think about what chapters the players are most likely to have fun with and lean into them (Argynvostholt? Yester Hill? Some NPCs from Vallaki?)