Ordo said:
Aunt Ashoka meets her Nephew.....tempting.....
Nah. Owen and Beru wouldn't let her anywhere near him. They didn't even want him hanging around Obi-Wan, and he's pretty much his Godfather. I doubt they would have anything to do with a strange Togruta girl showing up, even less so if they expect she has ties with the Jedi or the Rebellion. They both want him kept away from anything like that. Partially because they'd worry about him, and partially because they suspect he might turn out like his dad.
I don't see this happening at any point in Rebels, and that's the only place it has even a small chance of occurring. If it does, it should be shortly followed by Owen running out and telling her to get the hell away from him and get off his land.
They both know who Vader is if nothing else. I assume Obi-Wan explained what happened to their stepbrother when he dropped Luke off.
I also suspect they might be Imperial loyalists. Not greatly so, but Luke talks about going off to the Academy, and I assume he means the Imperial Academy. They probably don't have a lot of love for the Empire, but likely see the Rebels as a bunch of terrorists. Assuming Ahsoka meets him, she's probably with the Rebellion. Even more reason to send her packing.
I also suspect that while Luke speaks of the Academy, he's probably just using that as an excuse to explain his leaving when he joins the Rebellion. He seemed pretty enthusiastic when he hears about the Rebellion from the droids. I suspect his buddy Biggs had something to do with that. We see him later on in the movie briefly with the Rebels.
Luke speaking of the Academy the way he does makes me thing he's hiding his intentions from his aunt and uncle and that he thinks that they expect him to join the Empire when he leaves.