You’re able to minimize exposure to risk of market shifts and regulations changes and still make a good return on your minimal investment.

I will check my state regulations to determine how many I can sell without a license. 

What you’re trying to do would likely fall under rooming house regulations.  

It's part of the Fannie / Freddie regulations that these banks adhere to.

Jerry Brown did us a huge favor and created statewide regulations to allow homeowners to add ADU's.

You're not likely to get a private loan on a primary residence either, as those loans are automatically regulated and most Private Lenders don't want regulation headaches.If it's a straight flip, you can finance up to perhaps 90% of your project with a Hard Money bridge loan, but that may not jive with the Seller's stipulation for cash.Hope this clarifies things a little.

Dodd Frank made and executory contract more than 180 days subject to a lot more regulation and disclosures.

Is there a RESPA regulated loan?

And take the time to familiarize yourself with your landlord-tenant laws and other real estate laws & regulations (there are plenty!

I assume that each state regulates grandfather clauses.