It sounds like you are off to a great start already especially by educating yourself! 

It does beat the expected inflation rate of 2% set by the Fed.Rents will remain about the sameWhat’s interesting is they also expect:A 11.7% increase in existing home inventory followed by Single-family new home starts growing at an impressive 13.8%. 

My agent brought this deal to me and I jumped on it.

Sounds like a challenging situation all around I would  not cancel the deal, but if he dies and it goes to the estate and probate you may want to start looking for something else just in case...Best of luck. ...

I know the decision shouldn't be made of tax benefit alone but starting to think other areas may help me accomplish both more efficiently.

I’ve househacked a handful of properties and it’s truly the best way to get started!

Real estate is not my of my knowledge base at all but I want to start working on building passive income now (I’m 44). 

I found a lender and started the refi process. 

I’m looking to start a discussion on the best systems and tools brokers are using to efficiently run their business.

The interest rate isn't that huge of a difference between the 15 and 30 so worst case scenario if you have the 30 year option is you start paying it down on a 15 year timeline - sure you'll pay a little more in interest over the 15 years, but it will have been worth it if you bought another house.