The IRA is an account type or "wrapper" and real estate is an asset class like stocks, bonds, or commodities.  

A note is a bond, mortgages are generally exempt from SEC requirements but are securities.

So i kind of treat these investments as bonds.

So far, I have been investing my money myself into stocks and bonds. 

Lengthy job history or just starting a brand new job? 

I haven't invested in stocks and bonds since 2008..but plan to take my savings from passive income and active income and invest 75% in real estate and 25% in stocks and bonds either way (the bigger prop, or paying the loan off with the smaller prop)My only other debt is a 366k loan on an 800k rental property that brings in 48k per year in NOI after all expenses with a track record going back to 2009 so I feel that one is safely cash flow positive.

Loan losses and poorly performing loans cannot be eliminated and there is tolerance within the bond portfolio for the fall out. 

I'm not holding my breath, and intend to move forward with a deal today, but I wouldn't burn all my liquidity for a down payment with one deal at the top of the raging bull market we've seen in everything from real estate, bonds and stocks.

I can see a SDIRA as a good alternative when you already have a pile of cash in a 401k and want to invest in RE instead of stocks/bonds, but does it make sense when starting from scratch? 

Are you bonded, licensed and insured?