Can the "Other User" tile option be removed when using Defender Desktop Login?
If you apply the GPO setting "Do not display last user name" only the "Other User" tile option will appear on Windows 7.
This is an issue with how Windows 7 credential providers work: when a 3rd-party credential provider is used, such as Defender Desktop Login, then the "Other User" tile will appear.
There is no Defender option or setting that will change this. It's possible the way credential providers are displayed on Windows 7 can be changed, but please refer to Microsoft's documentation regarding required steps, etc.