We’ve started talking about the potential for collaboration, particularly to reduce construction costs by building simultaneously.

Then you subtract your expenses: (1) Fixed cost: property tax, STR insurance, utilities, landscaping, etc

Here's the deal:Purchase Price (PP): $95kRenovation Budget (via HML): $60kTotal All-In Cost: $155kARV (After Repair Value): Around $200kRefinance (via DSCR Loan): 7% interest, 30-year fixedRefinance Details: After the refi, I will pay back the Hard Money Loan (HML) at 11.95% with 3 points:HML: $60,000Interest/fees: $3,585Other costs: $1,800Total to pay back HML: $65,385After the refi, I will have $84,615 left in cash.Cash Flow & Expenses:Expected Rent Income: $1,700/monthProperty Management (PM): $126/monthInsurance: $100/monthTaxes: $126/monthMortgage: $1,043.75/monthTotal Expenses: $1,395.75/monthSo my monthly cash flow is about:$1,700 - $1,395.75 = $304.25/month in cash flow.Return on Investment:Cash Invested After Refi: About $18,385 (after paying off HML and closing costs).Annual Cash Flow: $304.25 * 12 = $3,651Cash-on-Cash Return (CoC): $3,651 / $18,385 = 19.8%I didn’t account for maintenance costs since it’s a full gut rehab, and everything is brand new.

I would encourage house hacking, you won't be cash flowing but it helps you save while you get your foot in the door with low DP.

what will be the most cost effective tool to evaluate residential properties? 

The home the owner is wanting is reasonable enough for the cost to build the home would make the "cost" of the property to be bought at a discount.

And the other way, if you’ve worked with someone who you absolutely would not use, please share as well so i can avoid them at all cost :).  

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

You may to buy them but getting a state/city specific lease that is reviewed by a lawyer is worth the cost.

On paper, a GC costs 10% to 20%, but it could be a lot more.