About the shape changing thing you might want to give me some sort of linkThe Yata Mirror can change shape and can give full coverage, so yeah.
Itachi couldn't maintain his Susanoo after the Kirin strike and that was for a split second, Thats not the case in CTNo itachi's susanoo and pretty much no susanoo bar perfect is going to be able to survive CT.
The rock that makes up the sphere is so compact that the KN6 bijuudama that blew up a big portion of konoha and is easily more powerful than kirin barely did any damage to the sphere. Itachi's susanoo would get crushed.