"He gets paid a fee directly from the funds he recovers from the person he serves. It comes out of a trust account. The court does not pay him."

Let's try it this way: His function is to collect something (we still don't know much), such as Penalties, settlement amounts, fees, whatever. Those go into a Trust Account. That is owned by some entity, such as District Court or County or County Court or City or City Court system. The entity then pays him.

The people he collects from are not providing a fee to him.

And the entity that pays him does so from the resources he collected. That means the service he is providing isn't to the people who paid those collected funds. What that typically means is the funds are Restricted, not from General (operating funds), and earmarked for the specific function.

If you read Pub 963, it covers how to understand if the entity is a governmental unit or not, such as, a Court District is formed and empowered by statute of the State. A Water District can be a governmental entity or a private entity. The water service can be a public or private water system, which is not the same as the governance (District). The County can require that a Water District gets formed, but it still might be a private district.

This is all "in my wheelhouse" as they say. There's too much give-and-take required to use an internet forum to determine what might be wrong here or not. But I find it hard to believe that a person not covered under the public retirement plan is also not subject to FICA, either employee/employer or SE. Nearly no one gets off scott free.

Obviously you have to find out what you need, get your evidence, and take your position on the issue. That's due diligence.