There's no such that as turning over parts of an arena while finishing others. The legal documents involve the entire building envelope, because much behind the scenes stuff (electrical, HVAC, elevators, staff access) involves more than just the public facing space. It's either an active construction zone, or it isn't, legally.
For a project of this scale, I don't see CSEC risking reputational harm for a rushed opening of secondary spaces. Keep in mind, nothing at the Dome is open 7 days a week, aside from the store. So regular hour restaurants, and everything that comes with that, is likely to open in stages