Pretty easy. We did it with 7 players. Levels ranging from 38 to 24. I am 36. Our Mewtwo has Focus Blast too so our Tyranitars mean nothing. They die even I dodged FB. Not a dodge glitch either since it automatically swaps the next Pokémon on my lineup rather than the enemy fighting an invisible mon. It's not hard to take down and it's also pretty easy to catch.
GamePress
How many people to beat mewtwo?
The invitations have gone to players of all levels but let's assume an average of level 30. Since its a small town we don't know how many will show up. Not all the regular players even got passes. We are looking to split into groups based on teams if enough trainers show up.
How does mewtwo compare to the other legendaries?