The place has at least one unpermitted room and a bathroom and a few other building code violations.Does anyone know how to navigate this hairy situation?  

Once my parents told me our tenants bathroom was nicer than their own I quit upgrading unless I had a complaint or there was a serious issue.

My other side would say "If you want to control your life, pay the cost, take the risk, buy your own house and have two bathrooms" but that isn't nice, so I try to stick to my pleasant negotiator side. ;-)

So I sent an offer in a condo that was priced for a great price great location all the appliance and bathrooms are brand new..

For the ground floor (non-permitted) we need to do some bathroom improvements which are not presently to code.

Have you considered adding a second bathroom?

Are the kitchens and bathrooms updated?

Hell it could be as simple as parking, laundry and bathroom services for truckers with some self storage....  

Investigating 1st floor leak would be quite involved with potential sources being bathroom above but hard to say.

. $3K per bedroom, $1700 for kitchen/dining utensils, $300 per bathroom, and another $1000 for miscellaneous (smart lock, modem/router, cameras, board games etc).