So now that the first dlc is out, will there be updates to the categories? Like Apocalyptic difficulty? And will stuff like NG+ allow DLC features and etc? (The same for dlc 2, too)

I think all DLC should be allowed. Banning it would mean (due to the royal ancient lab permanent upgrades) we would have to have a completely separate user just for speedrunning. This would take a while to get set up as you would need to do everything over again without doing one single DLC upgrade.