Respectfully, the FBI will not implement state court remedies by changes in the FBI's database. I have never seen an 851.8 order cause any change in the FBI database other than an additional entry re the granting of the Petition. The FBI does not seal, delete, erase, etc. Even if this jurisdictional conflict could be resolved (and Congress may do that at some point), all POST-certified employment applications cause an FBI report.
That is a well-taken point and I left it out my answer. I completely agree. Applying for many government jobs opens your entire history. However I have heard (anecdotally) from other attorneys that, after the 851.8, an individual can get a "detention certificate" from the arresting agency. This certficicate says the person is not considered arrested for the offense, but rather "detained for investigation." The DOJ is noticed to amend the rap sheet, too. Apparently this has been successful in, at least, changing the record from "arrested" to "detained" in DOJ's report.
Look at Penal Code secs. 851.6, 849, and 849.5.
I am fully experienced with the statutes you cite. But these remedies don't "change" the DoJ report, they only add to it. Fair enough and perhaps sufficient for many purposes. But this kind of remedy doesn't suffice for law enforcement applicants because no law enforcement agency will rely on the reported record for pre-employment investigations. All incidents -- arrests, convictions, infractions, detentions, law suits, restraining orders -- ALL incidents are investigated if the candidate's application survives that far in the selection process, and the agency relies on the underlying facts determined by the investigation -- not on the label or classification used by any reporting agency, including the state and federal governments. This is uniform practice in U.S law enforcement because all jurisdictions have sought the federal funds tied to POST-certification and standards.