Here's my idea for Kyoko's team:
Liepard: Aside from the obvious purple motif, Kyoko steals stuff and is prone to slinking around, both common traits of a Liepard.
Ditto: Ditto's an enigma with no real past, similar to how Kyoko is an amnesiac who tends to keep to herself.
Gengar: It's purple. And, um, I guess it's kinda shady. I'll be honest, Gengar's really only here because Hiro thought Kyoko was a ghost in Chapter 5, which is simultaneously hilarious and infuriating to me.
Croagunk: Croagunk was the partner of Detective Looker in the Pokémon games, and he claimed that it was the perfect Pokémon for someone in his line of work. Plus it's purple!
Espeon: Like our purple (!) kitty friend, Kyoko has very good intuition and foresight, to the point where she's jokingly called psychic at one point in the game.
Arcanine: Arcanine and its pre-evolution, Growlithe, were commonly used as law-enforcement agents in the anime, so I thought it would make sense for Kyoko to have a Pokémon which can literally smell truth. Plus it provides a handy explanation for how she got her burned hands!