Well, with so many characters either gone(Brock) or completely changed (TRio), it wouldn't surprise me if the writers give JJ&M the boot. But that is not the topic.
JJ&M want to steal Pikachu to give it to the boss. If they were fired from TR, then the only reason to follow Ash & Co. would be to prove that they are not failures and they can successfully steal Pikachu.
While Jessie does has contest, she was so upset at losing the Sinnoh Grand Festival that she threw her outfit away (I'd be mad to if the majority of my contest wins didn't get enough screen time). If she isn't a Coordinator, she can always try to be the actress/ celebrity she tries to become. Weather Woman is out of the question though
James, I'm not sure what he'd do. When TR split up in the noodle episode, he tried to catch a Metagross by himself to tell the boss its capture was a team effort, as to try to pull the Team back together. He'd want to stick with his friends even if they were not TR members anymore. He can't go home, or his crazy fiance(SP?) Jezebelle will hunt him down and drag him to the alter. Although we see James has a flare for
crossdressing PokeRinger, so he can try that.
Out of the three, Meowth is obsessed with Giovanni's approval the most. His desire to be top cat stemms from his dreams of being rich and powerful enough to rub it in Meowzie's face, the face of the she-cat he onced loved, only to be called a freak. Being fired from TR would hurt him greatly, meaning in his eyes that he is a loser who is unable to amount to anything. This is not true, of course, as he still has his friendship with Jessie and James, along with great money managing (when not broke) and Noodle slicing skills. I could see him returning to Christopher's resturant to be a fine noodle chef.
However, all three members of the trio deeply value their friendship. No matter what happens, they are always together. I belief that if thy ever leave TR, the three (plus Wobbuffet) will stay together and try to reach for the stars together. Since the TRio are such masters of disguise, I think they'll create their own fashion line and become stars of the fashion world. Jessie will be the model, the
Flaming Moltres James will be the head designer, and Meowth will be in charge of bussiness affairs. The three will become rich beyond their wildest dreams, and finally get their happy ending.
A guy can dream, right?