For the sake of the story this are the characters with their age and pokemon. This story also takes place after diamond and pearl story arc and before the black and white saga.

Ash: 16, Pikachu, Swellow,Bayleef, Buizel,Infernape,Donphan

Misty: 16, Azurill,Gyrados,Corsola,Starmie,Horsea,Politoed

Brock: 19, Marshtomp,Sudowoodo,Chansey,Croagunk,Crobat,Forret ress

Tracey: 18, Scyther, Marill, Venonat

May: 14, Blaziken,Glaceon,Venusaur,Skitty,Wartortle,Beautif ly

Max: 11, Treecko

Dawn: 12,Piplup,Buneary,Pachirisu,Mamoswine,Togekiss,Qui lava

Jessie: 22, Wobbufet,Seviper,Yanmega

James: 22,Carnivine,Mime jr.

Meowth: 10 (pokemon years), 20(human years)

Drew: 15, Roserade,Masquerain,Flygon,Absol,Butterfree

Leana (Lea): 18