The rehab took WAY too long, but we were attempting to keep from using of our HELOC to cover the rehab, so we were putting about $2,000 a month of our income toward the repairs.

You could even utilize the equity in the property by refinancing or getting a HELOC to buy more investment properties if it is something you want to scale up. 

Wouldn’t I have immediate equity in the new house that I could apply for a HELOC and use for the next purchase?

I can leverage my heloc options bank loans run a interest rate of 5% interest only and usually about .5% of a point .

Currently I own a home in West Palm Beach, FL and have about 95K in equity, so i would be able to get a HELOC for about 50K (Pending approval).

You can buy your sister out probably using a HELOC because you said you had 15 years as a homeowner use the HELOC buy her out rehab the property refinance it and there you go

We own the property with an existing HELOC with a balance on it against the property. 

I want a refi with the lowest possible rate and am willing to keep monthly mortgage payment equal to or below my current pre-refi loan which is $1420.I have 17 years remaining on current 30yr loan @5.3% interest plus an additional $19k @8% HELOC w/$19K balance.

They should merely be providing you their best options available for your needs and not attempting to influence your decision making.If your goal is to expand your portfolio, as good as having that additional cash flow sounds, it completely counteracts the option to grow as it will significantly impact the cash you have on hand for future down payments.A HELOC or home equity loan is a cool arrow to have in your quiver, but with rates on those products being higher than almost any conventional loan at this point, I would use it sparingly.

I have used the HELOC strategy before and I personally like it.