IMO the transaction costs to pull 40k seem like they might eat a chunk..... i would wait and save esp since seller wants to wait in any case.

Hiring a lawyer to perform these tasks you mentioned is overkill and will needlessly eat into your spread.

Closing costs and mortgage recording fees will eat into that.  

My tenants are refinery contractors (welders, pipefitters, boilermakers, etc.) and are going to be here to work 12 hour shifts, eat, shower, do laundry, sleep, repeat for about 3 months.

I can see a month to close, then however long it takes for the permit eating up a lot of the 90 day period to get everything done. 

Its been eating me up that I have these rentals with perfect roofs for solar and not doing anything with them considering climate change. 

Roofing, plumbing & electrical systems, HVAC and foundation are usually your biggest "eat it" expenses that may arise in a rental property - meaning most everything else can (if necessary) be DIY or have less expensive alternatives.

If you discriminate against any protected class here, the housing court will eat you alive. 

@Dean Letfus I wouldn't want a secondhand fridge from anyone who eats Marmite either!! 

My guess is a lot of SFH investors are not being honest with their maintenance/CapEx outlay and are eating their golden gooses one bite at a time.