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? 

This deal, i used my first successful buy and hold property and pulled a HELOC to secure financing and reserves.

Quote from @Matt Meier: Good morning,I’ve come across a renovation property available at a significant discount and would like to secure it without going the traditional 6-month financing route.

However, deeds in lieu of foreclosure can be subject to judicial attack by their grantors and their grantors' creditors.Grounds for attacks on deeds in lieu of foreclosure include the following:• That the deed was an equitable mortgage - that the parties intended the deed to be given as security for a debt and that the deed was not an absolute conveyance.• That the deed is either a preferential or fraudulent transaction within the purview of the provisions of the federal Bankruptcy Act or any other related state law.• That the deed is a device to clog a mortgagor's right of redemption.• Unfairness of the consideration.• Coercion, fraud, oppression, duress, and undue influence.• That the deed is not subsequent to the execution of the mortgage but contemporaneous with it.• That the grantor/mortgagor was insolvent at the time of the execution of the deed.An estoppel affidavit (executed and acknowledged by the grantor/mortgagor, attesting to the fairness of the transaction, the consideration exchanged, the value of the property, and other factors showing an intention to make a genuine transfer) or a recital (inserted directly in the deed) are supporting documents used to forestall challenges to these transactions.State law and local title standards must be consulted in regard to the consideration and treatment of deeds in lieu of foreclosure.What a GREAT post!   

If you have that experience, you probably don't need much marketing, as sellers will be reaching out to you directly.Focus on securing one listing at a time and building momentum.

I will secure the loan for everything.

Social media seems the best resource for this nowadays.Out of curiosity, what recourse do LPs have when GPs fail to operate according to the operating agreement?

I’ve heard that this neighborhood doesn’t really have any problems from a social worker but outside areas aren’t good. 3/4 units are currently rented at $900 each, renters pay utilities.

Which one is more appealing - continuing to own the house or the security of that much cash/liquidity?

Securing Lending shouldn't become a hurdle is the Deal numbers works.