I've thought of cash for keys, but out of principle, I want it want his record so this does not happen to any other landlord. 

I appreciate your enthusiasm and admire your work ethic! 

Understanding financial markets, economic principles, and investment analysis will be very beneficial, especially with property valuation, investment analysis, and financial management.

Could be perceived as an Ethics or Fiduciary violation... 

The people I’ve encountered in my 40 + years as a real estate investor and private lender who are successful have the following in commonThey are educated as to principles of real estate; real estate law; and real estate financeThey LEARN something new about real estate investing almost every day, and are open to realigning their strategy, tactics, and portfolio to encompass new information and knowledgeThey SPECIALIZE either in a strategy, property type or geographical area, and become EXPERT in that areaThey have survived real estate “depressions” where property prices have dropped 20% - 50%They understand the difference between real estate investing, operating a real estate BUSINESS, and having a real estate job.They network, for knowledge, capital and most importantly DEAL FLOWThe key thing to consider when you watch a YouTube video, take an “introductory” seminar, or read a guru’s website, is what is the subject persons BIAS?  

Major issues, numbers just aren’t that good, hiding something and wholesalers aren’t bound by the code of ethics to disclose issues like agents are etc… We also have a competitive off market, market.

 I am also looking at the HELOC as a 1st and use the principles proclaimed in the Replace Your Mortgage pitch which I understand to be, Use it as a checking account and putting all your income into the HELOC and then pay bills from that account thereby using all income to more quickly reduce the interest. 

Am I going to have a first position lien on the property and you'll pay me essentially a mortgage payment at 10% interest so each month I get principle plus interest?  

Do not over-extend yourself and risk taking a large principle loss.With all of that said, a househack gives you more control than most other options.

Always a good sign of a legitimate and ethical business.