The properties are well located in Denver with value add potential and all rents are currently well below market. 

I would keep detailed records of my deals to include photos that I could use later when I am approaching a potential funding partner.

You are still going to have holding costs and a heloc will just have less holding costs that you would if you were doing a personal line or hard money. 

(It’s multi-family but not entirely stabilized.)Rehab Costs: How much should I budget for bringing vacant units to market-ready condition?

Of course when doing the 1031 exchange your basis will carry forward into your replacement property.Where you have a potential issue is establishing your intent to hold those properties but immediately selling one or more them as soon as you have them ready. 

EDUCATE YOURSELF - yes, it will take time, but will lead to a selection that better meets your expectations & avoids potentially costly surprises!

I manage 400 rentals and the most significant claim ever filed was a kitchen fire that cost $20,000.

Because of cost, duplexes are are a better choice and compete well with SFH and or apartments. 4.  

Only extended exposure to your preferred market allows you to have this clarity and understanding about a property’s long term potential.

That's three months of mortgage and utilities, the cost of flooring, and the cost of painting.