If so, then it should be a tax free sale.

From my experience, since tenants typically pay electric, they would directly pay for powering the window units versus a central unit which the landlord would pay for.

You need to read the IRS Publication 523 that deals with the Sale of a Residence.

I worked with people here in Los Angeles that buy and refurbish properties for Tennent In Common or TIC sales and exit strategy.

What kind of sales and marketing levers can you pull?

Thinking about your refi fogs up the picture.The old properties: same tax position as before refi, absolutely no change.The new properties: your capital gain, if any, is the difference between the full sale price and the  full purchase price, regardless of financing.

Sales price: $900,000Seller finance: $400,000 / 2 year ballon / 7% interest rate / interest only monthly payment: $2,333 / no pre-payment feeEstimated monthly income: $9,300 / Annual: $111,600Electric separated - water $450 per monthProperty taxes: $16,700 (with property value assessed)Property Insurance: $6,300Renovation Repairs $150,000I anticipate the Re-fi appraisal to come in at a conservative $1,150,000. 

Purchasing power?  

Experienced investor, first time auction bidder...Hello BP family,  I'm venturing into county auction sales but this is what they stated in their Q&A section (Below). 

Some flippers who mis-timed the market may default, but these will be a small number of properties relative to overall sales and defaults.