I have been told by a contractor that the foundation of the building is intact, so it does not need to be torn down but requires a "gut renovation down to the studs."

No building inspections or permits exist out there.

It's difficult to see how a tenant will be after screened and signing a lease.

Just would like to start building relationships with people In the Phoenix area as well. 

My goals are to start building an investment portfolio of professionally managed (I could tell you all the reasons I will not do it myself) multi-family properties and, in time, develop a property in the Northwoods (Wisconsin/UP).

Building a 4,000-square-foot, three-story duplex with a 1,000-square-foot ADU could cost about $1.83 million, including construction and permits (excluding land).

Bonus Tip: If this quadruplex is out of state, I’d highly recommend building a reliable local team (cleaners, handymen, etc.) and maybe consider hiring a co-host or VA to help with day-to-day tasks, especially if you scale up. 

If anyone needs a GC once the designs are done I can build/renovate the project.

I was fortunate enough to inherit a 21 unit multi family building.

It is one of the reasons rent by room is more difficult to manage.I have no experience with rent by room and the associated common space.