@Reden Dionisio I'll answer your second question first. The short answer is no, if your loan gets sold whether you Cash out or have a HELOC will not make a difference.
When deciding between a HELOC and a Cash Out Refinance I always consider what am I going to do with the money. Each of the options have pros and cons and you need to consider your plan before choosing an option. Below I have some quick thoughts on why I pick one vs the other.
Heloc: its a line of credit so its great for short term uses. I currently use a HELOC in my flipping business because I know the time horizon of the capital is short. Most heloc are adjustable rates so if you lock in the money long term there is the potential of the interest going up.
Cash Out: You pay interest on the full mortgage plus the cash you take out. If I do a Cash out I generally want to know I have another long term vehicle where I can reinvest the cash. When you cash out typically your cash flow will decrease but if you can buy another asset then the net of the 2 is a gain.
Hope this helps in your decision. I'd love to hear which one you choose.