Unity already has a beta version being tested by some developers and will probably make support available for it shortly after the device is out. That Crossy Road game they demoed was made with Unity. It was just made public but companies with a stake, especially companies like Unity Technologies and Epic Games should have been told a while ago.
But you are right, it shouldn’t be too far a deviation from iOS so hopefully not that much work to add support for. I know there are some gotchas like a more heavy reliance on streaming, as strangely apps are not allowed any local storage. They must use iCloud for that. You will also want to take advantage of App Thinning and on demand loading as you have a 200mb app limit.