Ōban Star-Racers/WMG

warning: many spoilers follow

You can be Avatar more than once in a row

Satis had faith in Molly, but deep down he was uncertain about whether any of the racers had it in them to govern the entire Galaxy. Thus, he entered again as Super-Racer, aiming to have the seat of power for himself once again, if only to keep Canaletto out of it. When Molly defeated Super-Racer, he dropped out and acted as an overseer for the Earth Team all throughout the Oban cycle.

O was the vice-Avatar

In a flashback, we see Satis trying to use his magic to counter Canaletto's and crying to O for help. Thus, O had originally planned to race for the seat of power himself once his superior's turn ended. He even scored high at first. But as Satis became more and more determined to have Molly take his place, he instructed O to started throwing the races to allow her to step ahead.

That's one of the reasons he helped Molly, Jordan, and Aikka out on the second-to-last episode. A racer intending to win would have headed there in a hurry to nab the Ultimate Prize for himself.

Canaletto's mind is still alive

The last actions we see him do involve him using mind rape hypnotic sorcery on Eva just before his body is vaporised by Jordan. Canaletto saw it happen and had enough time to implant himself inside Eva's mind without her or Jordan realising. Now he bides his time, letting Eva live out her life unaware, until he can make a move to regain his power in the sequel series.

He saw that this was a possible future so he didn't just prepare Eva to become the one to release him. He prepared her as his potential new vessel.