I had a magic question when I was a landlord, I learned it from a friend of mine and used it with great success for many years.
When you call their references, explain who you are and why you’re calling, then ask a couple of really simple questions to put them at ease. How long have you known X? How do you know X?
Would you rent a room to X?
Then slide in the money question; “Have you ever known X to not fulfill a financial obligation?”
The answer isn’t nearly as important as the pause. When phrased this way the reference will think about that dispute with the last roommate, or the bet X welshed on at Superbowl, or when the screwed the cable company.
It’s a telling question and it served me very well through the years.
If it’s shared accommodation I would definitely cover entertaining. A friend over for dinner? No problem. A couple of friends over to watch a movie? No worries. Girlfriend overnight? Your call to make. What if the girlfriend is there 5 nights a week, overnight?
What about the yard? Can they have 5 - 10 people over for a bbq till 2 am? Can they take their ghetto blaster out into the yard?
One other thing I would cover would be bringing your drunken friends home. You make the call, but make sure the other person is aware of the rule before they rent!
Good luck to you!