I'm not completely sure on what you're trying to accomplish but when using specializations (inheritence) objects on the higher lever (generalized) will not be objects of a lower level (specialized).
Let's say I have an entity vehicles and a specialisation that enherits from vehicles called cars and a second entity called bikes. When I enter data in the bike or car entity, they both will be available in the vehicles entity as they are both vehicles. If I create a record in the vehicle entity they will only be available there as a bike and car are vehicles, but a vehicle is not nessarrily a bike or car.
The same is true for your users. The users entered in the system module are not accounts in the administration module, nor records in your own module's entity enheriting from the administration.account entity. This explains why you dont't see any data.
The fields in your screenshot are also read only, this has to do with the permissions setup on your entity and/or attributes.
I hope this helps you further in finding a solution.