Has anyone hired a single contractor to do everything exterior (site work, foundation, framing, roofing, etc.) for a new construction project and done all of the interior work themselves (or via your own subs)? 

Owner says roof was replace 8 years ago...

The liens will not be released by the city until all nuisance/unsafe-home violations are brought up to code (all exterior: roof, siding, windows, etc).

He confirmed what I thought that it needed a new roof and some electrical work done.  

I have 2 duplexes lined up that together would cost about $240k but both need roofs and some maintenance.

I remember when I was living in Boulder, I think the law was that no more than three people from different families could live together under one roof.  

Also, if there's a project that needs major work like a roof or siding, rewires or replumb that would be left in the hands of the PROS.

You may have to pay a structural engineer to do a review of the building to figure out what framing/roofing needs to be replaced.Any decent general contractor can help with the remaining estimates and repairs, get some referrals from other investors in the area. 

Needs a new roof (that was factored into numbers).

Although this is the first in my portfolio, we have ran a successful roofing and remodeling company for years, so my team is already in place and we are very familiar with this aspect of flipping.