Strategies:
Sheriff: You need to hit him with the ball to win a point.
Ninja guy: Go to one side and keep hitting the pickleball to that side. ONLY THAT SIDE. The closer you are to the net, the faster you beat him.
Scientist: Try to spin the ball as frequently as you can
Double ball guy: Hit the balls at the opposite sides of the arena
Hope that helps!
No tips for the champion, I want to see people use all their skill
Edit from 7 months later--for the twins, spin spin spin!
Also, just rediscovered a game from a notification. Thanks Xav iaer. Beat champion!