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? 

Looking to discuss with lenders on financial options.Please DM methankskaushik Sarkar

With the future being so uncertain I realized there was a need to do more than just rely on my job for financial security. 

@Tove Fox hope you find this copy & paste useful:)-------------------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

It could entice you to buy when you are not financially ready to buy.  

I'm not sure if that would bring in enough money but it would certainly make things easier financially speaking while you built up your real estate portfolio. 

Quote from @Josh Lansberry: You will hear a lot of people bad-mouth him, but Dave Ramsey can teach you how to get financially savvy real quick.

But everyone has their own unique financial situation, financial goals and risk tolerance.

I would not want to be the accountant at this firm though trying to track all of this, especially if they have to file consolidated financials -  Woof. 

Building a strong financial plan, researching markets, assembling a reliable team, and having an exit strategy are essential steps to success.Good luck!