Of course, noone realized these are the Outfits Jessie and James were wearing in the KANTO-episode “Jigglypuff’s song” [Episode 45] [I’ve no idea if this was the English title, but in Germany it was called “Pummeluff’s song” and it played in “Neon City”].
Answer: In the first episode Butch and Cassidy appeared. In Germany the episode was called “Cassidy und Butch”.
And yes, Misty was the only female main character yet who wear a cappy like Ash (even with similar colors *lol*). I loved that episode. I should watch it again. ♥