It is unlawful for an employer to terminate an employee for being a witness in, filing, or advocating the filing of a class action lawsuit to recover unpaid wages. It is also unlawful for an employer to terminate employees who participate in a class action settlement.
That said, no one on this board can say whether your employer will follow the law or not. Some do, and others do not. If your employer did terminate your employment immediately after the matter settled, then I would recommend that you immediately consult with an attorney about whether you should file a retaliation/wrongful termination lawsuit.
I agree that it is difficult to know what your employer may actually do. But I can at lease speak from experience. I've handled well over 100 wage and hour class actions and only received limited reports of retaliation by those employees who actually filed the case. I have not had anyone who didn't take an active role in the litigation report retaliation simply for sending in a claim form.
It may help you to know that the employer typically does not know or have any way of knowing exactly who accepts money from a class action settlement. A third party administrator receives the funds from the employer and then the third party cuts the checks (typically).
In California, it is against the law for an employer to retaliate against an employee for reporting or participating in a wage claim against an employer. If your employer terminates you for participating in the class action suit, you should contact an experienced employment law attorney in order to determine whether, based on your specific situation, you may have an actionable wrongful termination claim.
Since you are a member of the class, you might want to consider posing these questions to the lawyers who represent the class in the ongoing litigation. You've probably got their name and phone number right in front of you in the notice you evidently received. You may find they are happy to speak to you.
This response creates no attorney client relationship; consult a local lawyer for help if you proceed.