Just me speculating here but if the Lake Zone is to be more on the side of hospitality, hotels and recreational areas. And the Core Zone is theme park use. I’d imagine to put in any second gate, they would have to build a large multi story car park to open up more land area. Inevitably I see them starting off with a surface parking area as it’s cheaper.
This is unless they have plans for other land uses in the area. The park itself will obviously have a number of years worth of expansion areas built in. But personally I do see a second gate if all things progress well for them. There’s only so much attraction replacement you can do, as we see with Disney they need more attractions to pad out capacity.