When I interviewed with profs whose research interests weren't that related to mine we rarely spoke about their research. I was asked general q's about my research interests and we sometimes built off that (even if it's not their area of expertise, they can most likely still talk about it) or was asked broader questions about why I wanted to go to grad school, why I was interested in my particular field, etc.
In terms of not meeting your POI I do think that's a little strange unless they happen to be out of town or something - I agree that politely requesting a meeting would be a good idea. If there's a reason they can't meet with you during the interview visit, I'd think they'd at least agree to talk to you on the phone/Skype at some later date.