In my humble opinion the ball needs a little extra. I'd suggest giving it flying or some other way of evasion. That would fit the flavor and make it a bit better.
Make Ball indestructible, and sacrifice it when Orianna leaves the battlefield . Kind of like a reversed Phylactery Lich. (My two cents on making her more OP).
Great cards by the way, enjoyed them all so far
But honestly, her token reminds me of Kiln Fiend.