I own a rental property in Huntsville (SFR) outright and would like to leverage this investment with refinance or HELOC and use this money for the next SFR purchase in Hunstville area.

Would you get a HELOC to purchase another property?

Another way is to get the HELOC on the house.

I don't know the details of your finances, but assuming your debt free and dont need the income, refinance and then get a heloc on it.

I also use a HELOC on my personal home, partially because that allows me to keep my other cash moving. 

Many HELOC is considered same as cash. 

IF YOU CONTINUE SERVICING THE DEBT ON A PROPERTY, A BANK CAN'T DO ANYTHING REGARDING MAKING YOU COVER A PRICE DROP (Except maybe freeze HELOC).

I've explored HELOC's for help with a down payment but, to my surprise, they are expensive too and would take my positive cash flow down to just about nothing.  

I checked into getting a HELOC on my residence to starting investing in properties and found out that I have $200K equity if I want it with terms at .65% the first year and for years 2-5 3.50%, then market rate thereafter.  

If you're going for low income properties like we did, we took out personal loans, 401K loans, and a HELOC.