I think people in this thread are getting a little hung up on the fact that there might not be a clear-cut or widely-accepted definition of "REST". And, sure, if you're only passing people who happen to mention the exact keywords you have in mind, then I'd say your interviewing methodology is flawed.

But I don't think that's what you're doing. I think you're hoping to spark a conversation about what REST is and you've given us a few keywords here as examples of what you might expect to come up in this conversation. And this seems perfectly reasonable to me. I would expect that an engineer with relevant experience and an inkling of insightfulness and professional curiosity would be able to hold such a conversation.