First thing would be the suggestion for a new flags that control whether or not peds and vehicles can spawn at stations or patrolling only: something like SpawnsAmbientlyAtStations and SpawnsAmbientlyOnPatrol (SpawnsAmbiently would remain unchanged). The thought occurs, however, if creating Loadouts that are only peds or only vehicles would already accomplish this.

 

On the topic of props, would it be possible to set specific props after randomizing? In my example, I'd like random glasses props to be chosen, but set a specific hat prop afterwards (in this case, no hat, if a value of -1 even works that way).

Probably not answering your question but thought I would chime in to what I did.  I changed the Paleto Bay Sheriff station to a SAHP station.  An older mod on here that changes the signs and logos of the Paleto Bay station to a CHP theme/SAHP name.  Then I made that station spawn my add on SAHP vehicles.  You would have to go to the stations XML file and change to to SAHP/SAST then the HP's would spawn there.  They actually patrol there thanks to Jurisdictions+ though the map I downloaded uses BCSO to patrol Paleto Bay, because the Highway is right there and the Paleto Bay station is there I get a mix of HP and BCSO patrolling Paleto.  The problem I have is I can't seem to change the peds outfit to a SAHP uniform.  That station, in the back, 2 peds spawn in sheriff's uniforms. 

 

In Ultimate Backup, the special units, Supervisor I customized the uniform but can't randomize certain props.  That would be neat though.