Is it possible to wait for a face to face conversation, or are they making the arrangements now? I got the impression from your original post that this isn't necessarily something that needs to be taken care of this minute, although I am sensing a certain level of urgency in your posts. I think it seems a little less awkward for an in-person conversation along the lines, "I love this house. I think I'd eventually like to buy it from you, if you're open to the idea." I also think it'd be worth mentioning what you said in the first post about wanting to keep up the family traditions and hosting family dinners.

Is it possible to talk to your mom about this? She could always bring it up with her parents. She might also be able to give you some insight into what your grandparents are thinking, and also if there would be any resistance from your uncles.