I'd really appreciate experienced investors to take a look at my work and let me know if my assumptions are sound or if I'm completely off base.

As to the BRRR thing, that's an old tactic, buy n hold, you're a victim to financial changes along the way, it is not infinite as the gurus claim, you have loan concentrations as you acquire more financing, your available LTVs will drop as inventory increases and hard money doesn't last for the long term.  

I read about HELOC, which i always hear but i think you need to complete the duration of the loan otherwise you will be penalized :(.

That being said, in the current interest rate environment, I would lock in as much fixed debt as you can and avoid ARM's completely.  

The need is for a GC to oversee and carry out the completion of a rehab project.

Renovations are being completed within the next few weeks, at which time the property goes on the market.Scenario 1 - The property is sold, my note is paid back, and I receive 20% of the net profitScenario 2 - The property is re-financed, my note is paid back, and the property is rented.

Since it would be completely funded by them they would get 80% as I would only take 20% of any net profit whether it is lump or monthly.

Together, we have successfully completed 5 wholesale transactions in Galveston and 1 here in Denver. 

Since it would be completely funded by them they would get 80% as I would only take 20% of any net profit whether it is lump or monthly.Any suggestions?

This is a complete tangent, but this also illustrates why I think living in high cost areas and investing in them is a great idea.