There is a free website that I use to find the estimated short term rent based on Airbnb data.The same information you can get from airdna but you need to pay for that service.

I think 5% is a pretty standard rate to estimate with, but beyond that you might be higher or lower depending on your approach to landlording. 

The cash flow borrowing full cost via heloc will be marginal, possibly even negative if using realistic expense estimates (I.e. something near the 50% rule).  

Do I draft the contract price for higher than the actual build price that would include our estimated profit (sell price) or would a separate agreement between the lot owner be sufficient enough that outlines the deal since we don't know the actual sell price until it goes to market?

For example, their rent is $2000, they pay me $1000, I then apply the $1000 to the renovation project, which they estimate to be around $8,000.How should I write up the lease agreement as far as collecting the rents?

I am planning to include the estimated property value and the funds that will be transferred into the business bank accounts.

Is the 5 property ceiling (estimate, of course) because of debt to income ratio?

@Charmaine Alard why don't you start with comparing the rent you charged your friend vs the rent you could have charged according to Zillow Rent Estimate or Rent-O-Meter.THEN compare that to what a PMC would cost.

Many cost segregation firms will provide free estimates of the accelerated depreciation along with pricing.

He's getting numbers like $80K for a 2Bed 2Bath single family homes, additional $20 for rehab, so total under $100K and rent estimate is around $1000.