BallyHo, welcome to forums.
There is no reason to hide SuperSu. Hidden (without an icon or something) or not the phone is rooted. You cannot change that fact.
If it is rooted or not, a factory reset will wipe all your data/documents. There is not a single phone that can avoid such thing.
The antitheft features are to find your phone, to lock it or even to be sure it was wiped.
But nothing can avoid a technical thieve to manage your phone, rooted or not, disguised or not, hidden or not.