Downside is your cash is tied up for 6 mo's.It's a good rule of thumb to treat a HELOC like a credit card that you pay off as fast as possible. 

Namely that you can't transfer title on a property to your name (or anyone else, such as gifting it to a child) without the IRS treating it as a sale.

Treat it like a normal deal.

It is treated different than a liability/3rd party claim where there is one, full & final settlement. 

But a 2nd home loan that still allows you to treat the property with investment intent can offer advantageous terms compared to a regular investment grade loan. 

See how they are treating the apartment.

Pretty great strategy if you can find property management you trust everywhere you go, and don't get too caught up in trying to make a place tailored to your tastes rather than treating it as an investment. 

You should be able to treat this as abandoned, but consult with your local Magistrate to confirm what you are allowed to do.

Being a landlord is a long-term thing, things break, tenants get squeaky, tenants move out allowing you to rehab into better for more rent, but #1, its a business, so treat it as such.

Another refi pro is that you won't pay a boatload of taxes, which you will if you sell.With your family in the house for way below market rent, you're obviously not treating it like a business.