>>37232066At least Courtney and Shelly are involved in their teams respective plans. Their roles were expanded in ORAS and you fight each of them 5 times across the story including as a double battle alongside a subordinate grunt. They're involved in all of Team Magma/Alpha's plans and get charged with holding you back as they prepare the submarine for departure to seafloor cavern. They even altered Courtneys personality to be a creepy Tsundere singing type thing.
Plumeria fights you twice. The first is to tell you to stop picking on Team Skull Grunts, the second is for almost no reason, and then she does nothing from that point onward.
Her only notable moment is kidnapping Lillie which happens off screen and they could just as easily said she was kidnapped by Team Skull.