Hi, My name is XXXXX XXXXX I’m happy to assist you with your question today.
This matter is controlled by the ethics rules that govern attorneys, and there are no laws per se that would regulate it. Further, given the information you've stated I would not be of the opinion that ethics rules would be broken or any duty to other former members of the class action. I'll explain.
As to former members of the class the ethics rules state:
(a) A lawyer who has formerly represented a client in a matter shall not thereafter represent another person in the same or a substantially related matter in which that person's interests are materially adverse to the interests of the former client unless the former client gives informed consent, confirmed in writing.
(b) A lawyer shall not knowingly represent a person in the same or a substantially related matter in which a firm with which the lawyer formerly was associated had previously represented a client
(1) whose interests are materially adverse to that person; and
(2) about whom the lawyer had acquired information protected by Rules 1.6 and 1.9(c) that is material to the matter;
unless the former client gives informed consent, confirmed in writing.
(c) A lawyer who has formerly represented a client in a matter or whose present or former firm has formerly represented a client in a matter shall not thereafter:
(1) use information relating to the representation to the disadvantage of the former client except as these Rules would permit or require with respect to a client, or when the information has become generally known; or
(2) reveal information relating to the representation except as these Rules would permit or require with respect to a client.
Nothing in what you've told me has indicated that the firm hiring this former lead in the class action would be somehow violating these duties to former (other) members of the class. Likewise, the firms duty to the former (lead) member would not somehow be jeopardized by hiring him to do other work not related to the. Overall, as long as the lead members duties didn't somehow include work on the prior case or somehow taking a position adverse to the class. Then it would be an ethical practice and not malpractice.
I believe this answers your question. However, if you need clarification or have follow-up questions regarding this matter, I will be happy to continue our conversation – simply reply to this answer. If you are otherwise satisfied with my response, please leave a positive rating as it is the only way I am able to get credit for my answers. Thank you, XXXXX XXXXX wish you all the best with this matter.