the only problem with her being a kenobi... is two fold
1)she'd have to be a hidden relative of kenobi and the dutches..probably to protect kenobi and his standing in the jedi order. I can see that being a possability. and that kid had a kid and along came rey soon after.
2)in the book Kenobi, you see him as a broken down man, not willing to interact with anyone, let alone a woman who's starting to fall for him. with that novel, I can't see him dropping his ideals and suddenly saying 'frig it, lets do this thing...'.
so, if they do go the obi wan route, it'd have to be a secret offspring with him and the duchess.