So bisect the venture. 

So we need short term financing and understand there's a cost to take on the risk.

Use the top three or four discriminators so applicants can screen themselves.Then you need to have clear screening criteria yourself.

To me, this is a cost that won't "add value" to your BRRRR, so I would more strongly consider how much it might impact your ability to rent the unit/house.

So far, it's been challenging, but definitely worth it.

There are probably going to be other posters that endeavor to layout paperwork suggestions so I will leave something for other keyboard heroes. :-)With that being said what you were doing is definitely a gamble.

You could also call a couple of contractors on the phone and get rough sqft pricing from them for roofing, siding,  painting etc. like how much the averages costs are per square (100 square feet) and square foot .

So, your portfolio will actually be sucking cash out of your life, if you buy a traditional long-term rental using a HELOC as your down payment, for many years. 

Unless you do them all at one time, you have origination and closing costs on each house…so perhaps you pay up front to split the land.Obviously, I am not a developer and someone who is may chime in.  

Average rent in this area might be $1100-$1300/month if you have a nice property but this one is outdated so you would probably get $950/month.