To answer your question seriously though. Can you even take a HELOC for an originating second? Either way, I’d take the one with the lowest effective rate, factoring in closing costs and considering pre-payment penalties.
To my first point though, you’re not really considering 100% financing at this point, are you? Heck, mix that with some type of neg-am loan and it will blow your mind how under water you stand an excellent chance of becoming.