@Eric E.

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? 

Quote from @Greg Scott: Quote from @Derrick E.: I always play it by ear.

Quote from @Fareen E.: Quote from @Jaron Walling: Follow your lease.

If you are not Materially Participating, the loss will be reported on Form 8582 and like be classified as "Unallowed".The ordinary loss from Schedule E cannot offset the Schedule D capital gains. 

I got this e-mail too.

Quote from @Rebecca E.: @Katie MillerI came here because I just had my yearly with my new accountant.

E Equity, how much of the home will you own on day one.  

I googled it and found this:If you rent it to tenants, you would treat it as a rental and report it on a Form Schedule E.

You can however, write off the other unit as a rental on a Schedule E.