Zoning no longer allow "boarding houses" which is what you are proposing.
I live in a neighborhood of big old victorians that were turned into boarding houses in the 1940's - 1950's. The last boarding house here closed about 18 years ago.
Zoning in my city limits residents of one household to no more than 3 unrelated persons per unit. The Catholic friars up the street who went in together to buy a completely renovated (and gorgeous!) house for $850,000 had to get a variance for their living situation.
I've always pondered this issue. I like the idea of simple bed-sitters (that's what they are called in the U.K.) for single people, small units with a bed, sofa, and sink. The toilet is shared, is out in the hall. That seems like a practical and good deal to me. And actually, the bed-sitter places I've seen are pretty because they are in Victorian buildings with high ceilings and crown moldings, often with a lovely bay window. Those rooms can be handsome as hell and seemingly roomy because of the high ceiling.
But due to the kinds of people, low lifes, who inhabited our boarding houses here just a few decades ago, that kind of housing now has a bad reputation. I would be driven out of our neighborhood for suggesting that we go back to that despite its theoretical practicality.