1. I know its RNg, but what is its drop rate?

2. No one gets minato in our server through wheel this week event, and many draw into this. Is it possible that no one can get him in the course of event?

3. Should someone continue spinning the wheel after he dumps so much coupons to get minato?

Pls reply. Im helping a desperate friend spending large amount of coupons and his f2p.