You are quoting old rules.New rules have a calculated period of Qualified vs Non Qualified usage. 

When the IRA invests in real estate using debt not only does it have to be non-recourse but the IRS says, you can use leverage but since you aren't only using IRA money for this investment the retirement account is going to pay UBIT on the income generated because of the debt. 

If you are self-employed with no full-time employees you may wish to consider opening a Solo 401k instead of a self-directed IRA as it has several advantages over an IRA LLC such as much higher contribution limits, direct checkbook control (i.e. no need to have the account at a speciality trust company), ability to take a 401k loan, exclusion from unrelated debt finance income tax with respect to investment in real estate acquired with non-recourse financing, etc.Can I contribute to both a Solo 401k and SDIRA?

The house is located by 410 and I10 highway close to the medical center in San Antonio area.

My two cents is that the non-live broadcast is a commonly used marketing tool If it was "live" when it was first broadcast, then it is not a "scam" in my opinion but a rebroadcast that does not disclose that fact (not as professional as it could be).

I know that the general guidance is that emergency funds aren't to be invested, but given our financial security and the fact that we already have a personal e-fund in a safe, non-volatile location, would it still be crazy/unwise to invest this 15k in an S&P500 index fund in a brokerage? 

Which is fine, especially for non-American expats who can't get loans in their home countries.  

Austin was appreciating faster than non-tech cities.

Anything beyond that is going to take some blocking and tackling (reaching out directly to local companies like solar farms, construction, medical staffing agencies, etc.).

The "due on sale" clause is a non-issue here.