Pixelmon League:
Contains teams of 2 players that have to play 3 official games a week (To make it official, make sure an admin is there to supervise), if a team doesn't play all 3 games they will have a chance to make them back.
There will be 3 seasons a year, 16 week duration for all of them, at the end of each season rewards will be given out to the players (Rewards contain things like legendaries, shinies and much more)
Pixelmon World Tournament:
At the end of each season there will be a Pixelmon World Tournament. It will contain teams of 4 players from the same origin, an example of this would be (UK, US, Canada, Europe, Asia, Rest of the world).
If the results of a game are 2-2 then it will go to a final battle where both teams will choose the player they want to compete in the final battle (Usually your best player).
Rewards will be given to the top teams just like in the Pixelmon league. (Rewards contain things like legendaries, shinies and much more)