Xbox saves/digital transfer process

I'm not sure I can help with moving to an external drive as I've never dealt with that at all. Hopefully another Ambassador knows more and can help you.

As far as moving from physical to digital games: Yes, you will have to re-buy them. Basically the difference is, as far as I know, that a license resides on the physical disc which is what allows you to play that game. Buying it digitally means that license
is stored in way so that the disc is not needed.

The Xbox One and the Xbox One X are both backwards-compatible. There should not be an issue storing both types of games on the same console (I still play Super Meat Boy occasionally). The issue would be having to re-buy them if they were not bought digitally.
If they were bought digitally then they are tied to your account and all you would have to do is look up the game in the store and re-download it.

I hope I was helpful to you. Please feel free to reply if you have any other questions!

Your game saves are all stored in the cloud now. If you change systems, the save will load when you start the game up on the new system. Game saves and digital game licenses attach to your gamertag/profile. For example, I can go to a friends house and
log in to their Xbox and I could start downloading one of my digital games and when I go to play it my saves will load to so I can start right where I left off. To my knowledge, there is not an option to transfer game saves to an external device.

You cannot transfer game saves however all you need to do is log into your new XBox and all your saves will be there when it downloads your profile. ( "Any data for your games and apps (preferences, saved
games) syncs online when you sign in to Xbox Live, so when you reinstall a deleted game or app, your saved data comes right back with it." )

So all you will need to do is transfer your games from the hard drive to your external ( https://beta.support.xbox.com/help/hardware-network/storage/manage-storage ).

As for physical to digital you will need to rebuy the game unfortunately.

All of your game saves are stored on the Cloud. They will automatically resync to the game when you launch it on the new console.

It is true that you will need to repurchase all your disc games separately if your are selling the discs with your older console. However, I would recommend moving all your installed games to an external hard drive. This way you won't need to redownload
them when you buy them. The license for the game will just attach to your account.

The transfer process is not automatic. You need to manually transfer your saves one at a time.

On the 360, select your save and press 'Y' to upload for the Xbox One. Once the upload has completed you can select 'X' on the Xbox One save selection screen to download the save.

Repeat this process for all the saves you want to transfer.

Here is a video showing the process: https://www.youtube.com/watch?v=qbddTrt0i_c