Like to be able to use it when not rented, two young adult kids and their beaus.

Simply because they are innocent and cannot help themselves like a full grown adult

You would also face discrimination charges if you limit properties to male or female only. https://www.justice.gov/crt/fair-housing-act-1Personally, I would avoid renting by the room, because it puts too much liability on a landlord.

Well a rooming house properly run will never have vacancy but its running one such that you don't get shut down by code enforcement, then you owe the morgage and no income.The zoning that is common is;  3 unrelated adults. 

I am 60 years old with a husband and 3 adult kids.

I didn’t do parents as a co-signer (I don’t want to communicate with extra people) but I required them, or some other responsible adult, to be a parent guarantor.

I hope you lived here pre-COVID so you got to see how many community events Grayhawk hosts for kids (and for adults, but mostly for kids).

He will get a crash course in how real estate and real estate financing works, how to be a tough but fair landlord, and also how to adult.

She's a young 22 year old female, and stated she has no pets. 

Is he asking for a puppy or an adult dog?