can a undocumentated person file a unanomous clompaint to the labor commisioner?

They do have rights if they want to enforce them. I represent California employees in these situations and the hardest part is the employees do not want to get fired in retaliation and are scared to come forward, but if they would like to discuss possibly getting some help, I would speak with this privately as you are in a small town and the employer could find this posting.

My standard disclaimer: I am not offering legal advice, assume I do
not know the law in your state or at all for that matter and that I am
just making suggestions for starting points for when you do speak with
an attorney. Do NOT rely on anything I write and contact a lawyer in
your area immediately after reading my posting.

The employer is prohibited from taking action against those employees. If they work here, they have the same rights as citizens -- to be treated fairly.