Heavily vet out every tenant and read the fine print of every background check/credit check

I would think there is some fair housing law/landlord law that doesn't allow you to post a property you don't own, but if they seller gave you the blessing I'm sure it's fine? 

For example, I own a property with a roof that is absolutely fine but 20 years old and I cannot find another company to take it until the roof is replaced

It's fine for a single professor on the weekends but not a great situation for a young family.

Fine, I will watch their demo and report back.

furnace was fine when it was inspected and then breaks? 

If this is the case, you're going to be walking a very fine line between what you're legally allowed to do as an unlicensed entity, even if a GC does agree to put their name on the permits. 

Thus far it seems to be working out fine.

Please note that I am not discussing the business idea or the rate of return because I am fine with both and don't want that to be part of the discussion.

I've seen some comments state that it's all about the kitchen - only a small kitchenette with no stove is allowed (which would be perfectly fine).