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. 

Problem is it doesn’t exist as a “public” offering.  

My non-professional understanding is that those losses can only be used to offset income from that property.

I'm sure over time more laws will be created to force the government to give that information in a more timely manner but for now they often obstruct the public by withholding it for a time.

I have seen people buy non-existant properties, bottom of lake (literally underwater), slivers of land too narrow or small to do anything, Army bombing range, expired leases, cell tower now removed, property with 30 year lease and prepaid rent for 30 years, condemned buildings, toxic waste sites, land under railroad tracks, cliffs, landlocked property, wetlands, flood zone, unbuildable property, endangered species habitat, ....I have three rules for buying at Tax Sale:1.

Some events are free for members, while non-members will need to pay.

The rules are pretty complicated and the only people who really know all the terms and rules thoroughly are the Rent Levelling Board.Caveating that I’m not an attorney so go seek your own advice but I clarified a few things at a recent rent levelling hearing (which are open to the public and you can find the schedules with a simple Google).

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? 

Being a real estate professional allows you to treat the income as non-passive, allowing higher high income tax payers to pay less in taxes.

But the places we all encounter that could only have a wheelchair ramp put in that intrudes into the public sidewalk (which neither the landlord nor the tenant owns, and now the sidewalk may not be sufficiently wide or accessible for a wheelchair), or that would require tearing down the storefront's façade (envision a storefront right up against the sidewalk), are grandfathered in.