I even went so far as to show up with a box of dirty dishes and wash them while painting touchups from the movers.    

The lender costs are going to be a wash..when you pay cash first, you save the origination points and lender fees...when you refinance later to get your cash back, you pay them...the other transactional costs (title/escrow/recording are going to be the same..except you are going to pay them twice.  

So that first paragraph doesn't always hold.For calculating capital gains, certain closing costs at purchase are subtracted from the gain, so that can be a wash.

These days, they offer wash and fold services which they didn't have back then.

Definitely go with the car wash.

Remember sewer wont back up with just a home inspector flushing the toilet a few times.. it backs up once the home is occupied and EVERYONE is using the toilet and washing cloths etc.this is what I would do to protect my investment probably cost you a grand or so.. or just forget it and take what they give you but realize you will probably have some severe cap ex in the future. because these things wont be done prophylactically..  

Managing an Airbnb and go to the basement of my multifamily to wash some towels. saw like 30 alcohol cans, pills, powerball tickets everywhere and one of my tenants mattresses on the ground.

Wash, rinse and repeat!

Can anyone share a proforma to model NPV of just selling the vacant lot to a nationwide car wash ($1.5-$2M) - vs construction costs to build out for a QSR or something similar ? 

I'm comfortable with knowing that it could make it more difficult to sell in the future, however I would be purchasing it at a discount now so that part feels like a wash.