They both have purple hair (only in gen 1 for Agatha's case), their names start with A, and they are both Ghost type Specialist who appear in the game and end up getting in the E4. Sorry about my curiosity, I can be pretty observant at times.
Probably not. Ghost types are usually purple, so that takes down the purple hair similarities. The A names are probably a coincidence. As to the E4, I have no answer. Game Freak does odd things sometimes. I am not completely sure, but it is most likely a coincidence.