Lance is is a member of the Elite Four.
The Elite FourEdit
Agatha, Lance, Bruno, and Lorelei are present in the Indigo Plateau, where Rusty arrived without any appointment.
After Agatha's death, Lance and the two Elite Four trainers decided not to battle him, and he tells Rusty that they changed the rules and "officially" enlists Rusty as one of the Elite Four members while pleading him not to kill him and the other two. He also updated the Pokedex by adding Rusty's "Scary Magic Murder Bidoof" on the list, which he believes that Peanut Butter was a new legendary Pokemon.
After Rusty & Peanut Butter left, Lance asks if some of them should tell Agatha's family about her death, He and Lorelei disagrees, and this was pushed to Bruno instead.
Lance was most likely to be present as a member of the Anti-Bidoof Resistance, and he was unfortunately killed by Peanut Butter.
In the altered timeline, Lance was most likely to repeat his encounter with Rusty and joins the Resistance and dies again. After Peanut Butter restored his faith in humanity, he was most likely to be revived by his undoing.