When researching online, it looks there are some instances where non-vets can assume VA loans, but the veteran's entitlement would remain tied to the loan.How common is this and are there ever situations when this a win-win for both sides?

If you want to remain a landlord I'd hate to take a tax hit and lose out on a property with a long term tenant that is cash flowing.

With that said, I've done some research on the market and found the following information helpful in my considerations for Phoenix that you might find helpful as well:  Demand for both buying and renting property remains high due to the city's strong economy and growing population. 

It won't take much money to purchase something that makes sense.Use the remaining money to invest long-distance.

The 5% of the remaining balance late payment fee is a little much IMO. 

They have remaining years on contract- 1 is 5 years, 2 are 3 years, 2 are 1 year left. 

One can get a known median estimate of replacement cost, and can factor an inflation rate.

The plan was to utilize the HELOC as the down payment then getting a conventional loan to cover the remaining 80%.

Mitigation Strategies:Consider qualifying as a Real Estate ProfessionalGenerate passive income through strategic investmentsPlan property dispositions to release suspended lossesMake appropriate grouping electionsStructure leases to demonstrate active participationThe Bottom Line:Cost segregation studies remain a valuable tax planning tool.

If one tenant moves out, the property remains cash-flow positive.