I typically prefer to avoid condos since I can’t predict HOAs and you want to be informed on zoning restrictions in the areas. 

Forecasts/predictions aren't worth the paper they're written on, which is why I generally don't read them.

Military get paid BAH, which means rents are fairly predictable. 

I predict the local PMs will all be out of business within 8 years. 

Though, keep in mind that HELOC rates can fluctuate with the market, potentially exposing you to higher interest rates down the line.With a cash-out refinance, you'll typically have a fixed rate, providing stability/predictability in your monthly payments.

We are hesitant to give up a predictable income and steady cash flow.

I have a handful of rentals in Ramsey County - after a property is updated and sold the assessed value can jump up dramatically, but then the future increases are much slower and more predictable in the following years. 

What about leaking roofs or accidents you can't predict?

It's a business with incredible value in terms of stable, predictable revenue and as a retirement asset. 

If you truly want something that's completely safe and predictable, it would make more sense to invest the money into bonds or mutual funds.