Also, frankly, I'd like to avoid banks entirely, so I've been studying seller financing a lot.Here's my plan: I intend on treating this first house as a total investment, but will also be living in it for 2-3 years and house hacking by renting out two of the bedrooms.

Getting into a turnkey for $10-$20K leveraged 5X sounds pretty nice.3.Continue living in the current duplex while studying how to rehab houses, read fix and flip books, etc.

Erik Johnson Be sure when you interview a CPA ask about the passive activity rules, real estate professional rules, will you need to group future rentals together, can you deduct any losses each year, how does depreciation work and should you get a cost segregation study or asset management report done, which repairs can you write off vs capitalize, how will gain or loss be treated when you dispose of the property, how are the loan costs treated.....if they don't have a good feel for all of this move on to the next.

True professionals have valuable information, and are most likely charging for it.If you find someone who is where you want to be, put in the work to study them, watch what they do, listen to what they say, pay for information they have.The first step to success is to train your brain to seek information then take action,  not to wait for it to come to you.

What is the best source to study federal, state and county laws describing landlord/tenant rights and responsibilities?

PM me if you'd like me to send you a copy of the language we use. 

As per commercial non consumer purpose loans, it would depend on the language of the specific state's laws, rules and regulations regarding loans, contracts, torts, etc., whether or not it is considered predatory lending or if lender liability can be invoked on some other issue.The real issue for me is that even if it passes muster in a particular state, what happens if the borrower files bankruptcy and does so utilizing Federal guidelines.  

Are there any Brokers or Wholesalers in the area that are willing to connect and talk about this as we study the market a bit more? 

And study and become an expert in your market and know your sh*t inside & out when it comes to contracts, valuations, rehab's, etc. 

All too often investors study the numbers too deep and not the geographical location, companies and individuals they are giving their money, and not having enough money to make the investment move. 1.