He wanted a starter Pokémon from Hoenn like Torchic because they were "special", or a Pikachu like Ash Ketchum, who he seemed to have heard good things about. At the beginning of the episode, he didn't really understand the point in having Pokémon other than for protection. He didn't want the hassle of raising them and was quite spoiled and selfish, making lots of demands for evolved and rare Pokémon like Raichu. However, while accompanying Professor Oak and the others during the episode trying to recapture the escaped baby Bulbasaur, Charmander, and Squirtle, he begins to learn a lot about the feelings of Pokémon and grows to understand them. Gilbert eventually chose the Bulbasaur he'd helped save from a group of Primeape after he was impressed by the strength of Ash's Bulbasaur at driving them back with a SolarBeam.
Eliza is the whimsical daughter of the family Leagan of the Audrey clan. She is so haughty as if she is the lady in the family and as if those teenagers who are not her friends must obey her. Candy has been adopted so that Eliza gets a playmate. But Eliza often annoys Candy with her brother Neil, intends to harm her by intriguing and always insults and humiliates her by for example considering an orphan as a worthless being; however, Anthony, Stear, and Archie fortunately often protect Candy from her mean tricks.
Caitlin debuted in BW090, where she participated in an exhibition match against Cynthia in the Pokémon World Tournament Junior Cup. Despite how powerful the two Trainers were, the time limit put on the battle ended before either of their Pokémon could be defeated, making the match a draw. (Source: Bulbapedia)