There was an initial error with Ultimate Edition bonuses, but this has since been fixed. If you're still not seeing your bonuses in game (including the Halo: Reach Character Pack), please exit out of the game and reboot your console/PC. Bonuses should be deployed after the reboot.
Multiple Copies: Pre-order & Game Pass
If you have an active Xbox Game Pass Ultimate subscription AND you pre-ordered Gears 5 separately, then you may encounter a license conflict. Please reach out to Xbox Support for assistance.
If multiple users are playing on a single Gears 5 Ultimate Edition license, the bonuses will only be applied to one account. For game pre-orders, the content is applied to the first account that loads the game; for Xbox Game Pass Ultimate, the content is applied to the subscriber.