The only one who implicated "Nikki" as an illegal was her attorney, Gloria Allred. It's not ethical for an attorney to expose a client for another crime when the client retains you in another matter.
The Social Security Administration had exactly one communication with the Whitmans...none from the IRS...or Allred would have used that...and the communication the Whitmans did get was clear that it was not representing "Nikki" as an illegal.
Allred is not an unethical lawyer, Revere. Doubtless she has a release from her client to reveal that informaton. The fact that Allred does not have any IRS documents proves nothing; if she has them she could not use them. They are confidential to the Whitmans as well as to her client (and any other employee whose wage taxes were reported on the same forms) and could not be released without Whitman's consent.
But hey, if you think Allred violated the Canon of Ethics, call the California State Bar and report her.
Lawyer Regulation
Yeah, she's unethical. Her client retained her on an employment matter and Allred told the world the woman forged documents to get work...a felony. When Mark Levin, and attorney, pointed that out to her, she walked it back, saying she never said "Nikki" was illegal.
Show us where any agency of the US government ever communicated to the Whitmans that "Nikki" was an illegal. The chick herself said she came to the Whitmans to reveal that, and asking for help...and they fired her.