As a builder, I target about 15-20% profit per build ($500k-800k price range, low-mid in my area).

Thats good to hear it is resolved and sorry about the credit.

Financing and Exit Strategies MatterMany house hackers use FHA or low-down-payment conventional loans.

Just taxes will be 20k.I would run numbers like this:Property 1.5 million (minimum)Construction (Cheap end) 2.14 mHolding Costs (at least 150k)In my book, even according to your calculation, that means you put in at least (those numbers are on the low end): 3.8m! 

No social or credit pull needed upfront. 

You won't find a great software for free or a low price.

Fully furnished 6 month (maybe as low as it was3-4 months) is much closer to a LTR.  

I have actually cashed out a lot of my IRA now bc I have so much depreciation from RE that my tax bracket is very low and the taxes to pay on the IRA withdrawal are also pretty much non existent (taking aside the penalty). 

You have used home equity lines of credit to purchase investment rentals and want to know the best way to pay down the HELOCs.Between the two properties you bought, after expenses, you have $250 a month positive cashflow to use.What I like to do is pay down some principal every month with my positive cashflow.I use my extra active income from real estate commissions helping other investors to pay down the principal even more which just frees up that credit for me to use again.I know I can refinance the HELOC debt before it changes to principal and interest as it is just interest only payments as yours are.One difference is the cashflow, I have greater positive cashflow and could make the principal and interest payment in the future with the extra cashflow I already enjoy.I always get HELOCs on my income properties as well after purchasing them to pull out as much of my downpayment as possible.

Low value markets might be Pennies on the dollar like you allude to.