It’s been totally rehabbed but it’s in a frame 2 flat.

Total number of people that would occupy the apartment3.)

If I were to use 1031 exchange funds obviously the timeline is tight, so I may have to use temporary financing to close the deal and then refinance.

Other than the obvious 30yr fixed vs 20-25yr adjustable, any advantages/disadvantages of going single vs multiple loan?

You have promised already to build it. and they are good for the 137 total.

@Ronald Erwin totally unrelated to your question, but why sell the rental and rent your current home?

This interior change forced us to consider the short term rental market and how it could actually be a desirable feature for this market where a group may be interested in renting both sides like adjoining hotel rooms.Our total cash into the renovations was extensive ($95,000). 

Obviously Zillow has sold prices but I can't tell how if it was a foreclosure after it already sold. 

In this same area, a 2 unit duplex with 2, 2 bedroom 1 bathroom units would rent for $2000-2300/mo total and cost $200-250.

Yours will vary obviously, as I'm sure your kitchen dimensions are different.I normally don't buy from Lowes or Home Depot.