I've since bought five notes, and two private stock offerings.My parents have bought maybe five properties over the years in their SD IRA.

I'm not sure if these high tech salaries will continue, some of them get compensated via RSU (Restricted Stock Units) My suggestions were to house hack (if they're still renting) or within a 2 to 3 hour drive.

I want to learn all I can but it feels like I need to build a better foundation of the diffrent principles of real estate so any books or texts that you would recomend would be great.

This is not a "real estate rental income" activity as defined by the IRS, so whether you are a REP or not, you can take this benefit.All of this is separate from a QOZ Investment, which would require you to first recognize a capital gain from another source (say a stock sale), invest that gain, hold it in a Corporate or Partnership structure (likely partnership), meeting the substantial improvement qualifications of being a QOZB, and then yes, you get to avoid the depreciation recapture at the end of the 10 year hold period, at least for the portion of your investment attributable to the original gain that you invested in the project. 

If person X purchased 50 shares of stock at a price of $10.00 per share, their cost basis is $10.00 per share.

But I did the math and for me personally that was true, I'd pay off my mortgage 5 years early if I paid an additional $100 each month to principle. 

I've also seen people who squirrel money away and then lose it in the stock market or some other investment like strips or something . 

Whenever you subtract inventory and reduce the housing stock you get the adverse effects you'd expect.  

Ideally, I'd put more towards my principle faster if I have the cash.- Once I get 20% equity in the property, use another FHA loan to buy and live in another multi-family property then rent out both sides of my first duplex leading that to positive cash flow.- Repeat..Am I on the right track? 

It's only 3.5% down + closing costs and reserves.Work your day job, mow lawns, leaf cleanup, shovel snow, flip furniture, pick up night shifts waiting tables/bartending, stock shelves at home depot overnight if you hate talking to people or anything else.