Explanation:
You should change Guest user access to be more inclusive to allow User-GU-A to have the same access as UserC. With the current configuration of the User Settings and User Features, as shown in the three exhibits, Guest user access is set to limit access to properties and memberships of directory objects. To allow User-GU-A to have the same access as UserC, this setting would need to change to the most inclusive setting, which is Guest users have the same access as members.
You do not need to add UserB to the AWS-WS group to allow them access to My Staff. With the current configuration of the User Settings and User Features, as shown in the three exhibits, we can see that only the AVD-Users group have been added to the setting Administrator can access My Staff option. As UserB is already a member of this group, they already have the access they need to access My Staff, and you do not need to add them to the AWS-WS group.
Not only UserA and UserD can access the Combined Security Information Registration Experience. With the current configuration of the User Settings and User Features, as shown in the three exhibit images, we can see that the AVD-Users group is selected under the Users can use the combined security information registration experience setting. In this scenario, UserA, UserB, and UserD are all in the AVD-User group.