^
Unless what they now have planned for the entrance isn't too elaborate or extremely different, I don't see how they'll get it even remotely finished by January or even by when Potter opens from previous things I've seen.
Unless of course it'll be something super simple like new landscaping, new detailed pavement similar to what's in front of the Wizarding World entrance, etc, to spruce up the entrance before a larger project is started after Potter's opening.