So, my question is - how understanding/flexible is the FHA in these situations?

For something like a medical bill, I'd be flexible.

That gives you flexibility for if and when you refinance. 

On the plus side, you can transition to a more flexible plan document by working with a plan provider who can restate the brokerage firm documents if you ever wanted to.

Ken,As a whole, military personnel tend to be flexible and make the best of all different types of living situations. 

Selling it and paying off our primary residence would be an emotional win, allow us to pocket more of our income ("virtual cash flow"), leave us a little extra cash to purchase another SFR or duplex investment property, and allow flexibility for potential job transitions in the future. 

***I have a flexible work schedule and get free unlimited airline tickets*** I do not want to buy in my home state of Massachusetts and am hoping to move sometime in the near future (but probably after buying).

However, the HELOC is far more flexible than a Cash-out Refi since it is reusable and you can pay it back with a cash flowing property lowering your overall payment on the HELOC.

But I can’t seem to convince her that with having someone help us pay the mortgage I could have the flexibility of taking some days off of work to spend more time with the family and not feel so tied to work.

Beside from protection, it will provide you with flexibility when it comes to taxation, management and ownership.