Guess Shurelia had to quit being Administator sooner or later.

No that cant be. Each Ar Tonelico game centers on a different land mass. This has to be another adminstrator for the 3rd land mass. The armor scheme probably says something about all the adminstrators know each other. I wouldnt be surprised if Frielya had that kinda armor lying around that she just chooses not to wear. I bet its standard issue.