I used to live in a shared house for several years and learned the hard way some key lessons. Personally I would never live with an in house landlord ie renting a room from the person that lives in the house. It is a recipe for disaster because the owner will always have more power over the house than other people and it will always lead to arguments. Personally I would always prefer to rent a room from a landlord that does not live at the property because then everyone in the house is on the same level. That being said I would rent room out to people as the owner of the property as that is different as i would be making money in the process.
What I would recommend is setting out a few clear rules, the main one being around whether people can have "friends" or "partners" sleep over. I've seen it happen many times, I had a large three bedroom house rented out and sublet rooms to people and we let in two girls, it was not a month later that one of the girls boy friends pretty much moved in. We soon learned that he had even stopped paying his flat and had completely moved in without asking the other tenants. We had to force them to pay more rent and were not happy about it. I would suggest a policy of only allowing tenants to have friends sleep over one night per week, to prevent this problem I mentioned. It is not fair on the other tenants that have to wait longer for bathrooms and kitchens and put up with a more crowded living space than they might have signed up for. Of course being reasonable and flexible will go along way and if an occasional situation where a friends sleeps over for two nights because of some issue or something, I wouldn't make a big deal about it. It is more just to stop this sharing of rooms problem than being a house police man.
Outside of that main issue, you can decide what other rules you want but bear in mind the more you have the less likely people are going to want to live there.
There are some good channels on youtube that discuss this topic quiet extensively. I want to get in to shared flat rentals, we call them multiple occupancy in the UK, in London like San Francisco, there are millions of 20-30 year olds living in shared houses and it is a great market for maximising cash flow on properties. In the UK if the house has 5 or more tenants then we need a special license and have to abide by all these different safety regulations that can be costly. So check your local laws on that topic. Personally i'll try keep my houses to no more than 4 tenants because of this reason and any more houses can become too crowded, even if there are enough rooms and bathrooms.
