However, I've worked in the mortgage industry since 2001, primarily in the secondary market (i.e. mortgage bond trading, analytics, rating securitized mortgage bonds).

I send an email back to all inquiries (from a script I copy/paste) with basic property info, requirements, and details for open house times (typically one evening and one weekend, and hour in length). I

This will not have any direct impact on the fixed, long term mortgage rates as they are controlled by the bond market. 

I've asked if they are licensed, bonded and insured, and they say they are, and I told them that I will need copies before I sign a contract or pay a deposit. 

IMO, cash flow IS what REI is about, sort of like a coupon bond, you collect as time progresses. 

If you work with licensed, bonded, and insured professionals they will be able to pull the permits for you or guide you in what you need to do.

Workers bonded ?

You could also explore fixed income mutual funds or ETFs, but these may lose principal.For the balance, consider that 10-12 years is a long enough time horizon that fixed income instruments - bonds, CDs, or debt funds - are subject to inflation risk.

Age is a factor, family is a factor, risk tolerance is a huge factor, etc.Honestly, if you are posting this question on forums then to me it sounds like you have no idea what you want to do, so my recommendation would be to put it into your savings (CD's or bonds) until you determine how you want to put that money to work.

Personally, I search properties on the MLS that are "back on the market" or have a lengthy DOM.