And as the buyer (my colleague) is now getting closer to closing it's starting to look like it might be worth just cleaning the place out and doing a very low cost rehab (paint, pressure wash and handyman repairs) for a quick sale.

I am glad someone else called out the mansplainer above bc I was about to rip him apart and I try and remain civil on BP.

The home needed everything from stucco repair to painting the exterior and interior of the entire home.

An example of my recommendation to a new investor is to go buy a house with easy re-sale, that needs superficial changes such as painting, landscaping, new carpet, roofing, etc. 

We freshened up the interior with new paint, and a few new trim items, but mostly it was well landscaped and well cared for prior to our assuming the loan on it.

we cleaned up the exterior, painted interiors, added LVP flooring, bbq pits and picnic benches What was the outcome?

having an incredible onsite manager, adding colorful flowers to perk up the curb appeal, paint the windo shutters to make them pop and renovate the interiors.

Our office manager argued that all the proposed repair such as drywall, floor, paints, doors, windows, thermal and moisture protection treatment, etc are part of the tenant responsibility.

I can help you ballpark your ground up builds or renovations, or ad hoc questions like "What does tile/flooring/painting cost in $/SF?". 

Taking some of that space for the bedroom would only require framing in a non-load-bearing wall, closet, and bedroom door, plus adding a few electrical outlets/switches, and then finishing with insulation, drywall, paint, and trim.