Unfortunately his background and credit check came back stellar, he has a great job makes plenty of money.

My grandiose scheme, aka “business plan” has so far been to leverage my not-insignificant construction resume to get stellar yields out of properties that traditionally have not done well, and therefore force appreciation.  

A lot of buyers, especially Investors, just couldn't buy without Stellar Credit and Income.

In addition to the excellent advice above when you quit your job you will not be able to prove to banks that you have steady income and you will have to go stated or no-doc which is going to make it more difficult to get a loan, and next to impossible if you have less than stellar credit.

I have stellar credit (>800) and make about 2.5x the average income in my area.3) Should I or should I not use the HELOC to fund 20%?

However, Podcast 61 with your's truly is available on YouTube as well as audio, because @Brandon Turner and @Joshua Dorkin wanted to make sure and capitalize on my obvious stellar looks. 

Attracting Equity partners on your 2nd phase or new venture should be fairly simple to do with a strong feasibility study and your stellar track record on your current deal.

Then a stellar plan like Dawn’s has a chance of working.

What advise can you give a newbie to make this debut property a huge success?

(Hence the asking price, which is just stellar for that area)