There's an issue with pre-order items on Xbox One at the moment, they are working to fix it, but then again is not a priority.
It will get solved, but you will need patience (=
BTW you can equip Simon mask in Xbox 360 and switch to Xbox One and the character will have it, but if you replace it you will need to switch back to Xb360 and repeat.
These are the pre-order DLC's that are not transferring over to Xbox One
Classic Ghost Character = (Head) - (Patch) - (Background) = Simon Ghost Riley
Xbox Pack = (Weapon Camo) - (Reticle) - (Patch) = Spectrum
No Man's Land = (Patch)
Into The Deep = (Patch)
Federation Day = (Patch)
We are aware that players are not receiving certain DLC when digitally upgrading. We are currently looking into this and we will update the community once we get more information. We appreciate your patience through this time.