Bounties are mostly vanilla (with some mods like Vayra's Sector and Bounties Expanded replacing the bounty system), Nex largely doesn't touch them.
Well, which bounties are Hivers offering exactly?
- For the vanilla person bounties: If you don't have the PersonBountyEventData call then I dunno what's happening and can't help you, unfortunately.
- [EDIT] For system bounties, you may need to set postsNoBounties in the .faction file's custom data; see vanilla pirates.faction or luddic_path.faction for an example.
- For sector-wide bounties issued by a faction, they already shouldn't appear for non-playable factions, although this may not be working as intended. You can also make them go away by marking Hivers as a pirate faction in their Nex config, but this has other effects. Next version I'll check if the faction is participating in bounties based on the PersonBountyEventData.
To avoid being a target of trade missions (and some other mission types), I think you need to call market.setInvalidMissionTarget(true); on all the faction's markets. Nex has a faction config setting for automating this, although I don't think it applies to existing saves (until the markets change ownership); set noMissionTarget to true.