The only way to know would be to go and ask the new owners, which of course may be an uncomfortable conversation. However, I find that if you approach people in a sincere way, they're often receptive. Explain that you once lived there, and ask them if they've seen or heard anything weird while in the house. Anyway, you have a number of leads you can follow. Furthermore, it may be worth trying to scour public records. See what you can find about the land there.
That's why I never joined any ghost hunting groups. It's hard to do serious research when your work is constantly undermined by kooks who pretend to faint and then say, "a demon did it." Unfortunately, the whole field of the paranormal is such that it is a small number of dedicated people who take it seriously being held back by nutjobs, quacks, and grifters.
I think it's really a bit like making new friends. That is to say that you gotta take the time out to talk to these people, scrutinize them, and get an idea of what they're about. The nutjobs are usually easy to weed out, in my limited experience. They'll usually give themselves away almost immediately. Grifters, on the other hand, a lot less easy to catch.
Same here.
I'm a believer in the idea that if a human sees a UFO it's intentional. You don't see them by accident. They're visible to us only if they want us to see them.