Will my data save over from disc to digital?

Save data is separate from game data. So if you switch from disc to digital, or vice versa, you'll pick up where you left off.

It would still show on the console as 1 entity since the game data is the same on both. I believe the digital license takes over so it'll check your digital license even if you have the disc in the drive.

Game saves are separate from game data, but you would still be using the same save data whether you're playing digitally or from the disc.

Your save data will carry over as long as you are using the same account you played on earlier. Your data will carry over for both digital (from the Xbox/Microsoft Store) and physical version (disc from anywhere) of the game.

Digital copies work the same as the disc version. The data for the games themselves is separate from game saves, so using the digital copy vs. the disc will not affect anything else.

With the disc only being used as a key and the game actually be stored digitally. It saves you from worrying about the system trying to read data from a damaged disc. Faster loads less worry about dead game discs.