Saxton Hale's rematch team doesn't have fixed levels, and will have different levels depending on the Player's Pokémon's levels.
Saxton Hale is a character in the lore of the game Team Fortress 2. He is the owner of Mann Co., which is the company that supplies weapons and such to the two teams. He is most known for his presence in the comics, but he has also made appearances in-game via menus, as well as an official voice and model with the recent Jungle Inferno update.
His opening phrase is a reference to a near-identical spiel he makes in the TF2 comics.
Saxton's team is mostly animals, some being extinct, which is a reference to how he is known for being an adventurous man that has made many species of animals go extinct.