So far, all the evidence that has been presented shows only restrictions on unlicensed brokering, and that's it.Lastly, I can agree with your view that, "nobody is advertising the paper..." etc.

So far, I’m thinking about extra closets with locks, maximum number of bedrooms feasible (aiming for four or five), fireplace and some kind of a nice outdoor deck or screen porch, possibly a hot tub.

You may also be able to look up contractors through your state's licensing board and view past violations and fines.

Also, is it common for the owner of a multi-unit property to state that a potential buyer cannot view the inside of a property because they don't want to disturb the current renters?   

Assuming he viewed the property and did his own measurements he shouldn't have missed $200 worth of materials.I agree that additional scope happens after projects begin, especially roofing and other projects where you start to dig into the structure.

Generally speaking, Old Money has been in the family for generations and is kept largely hidden from public view.

She has offered to view a 3-plex that we liked and send me photos and a video with comments on anything that might be a "red flag", as far as the condition of the property. 

Screen screen your tenants !!!!!

Even the best tenant screening can’t guarantee a cooperative tenant Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I have a couple of 4 plex units in Mountain View, a few condo's and a commercial residential in Oakland and I have an industrial building in Milpitas.