I think it'd be really cool if there were some NPC's from Xystsus's NPC Pack in the MMO. Maybe you could do something with the army NPC's, like some kind of military outpost. And the zombies too, as well as the snork's and bloodsuckers. Maybe even some of the Alien NPC's. I don't know, I just think it'd be a great addition to the MMO. I just think that this gamemode should be very enhanced by the community made projects here, especially NPC's to create a diverse world where you don't know what to get.
No. Xystus SNPCs tend to crash the server.
Besides, as Klaria already said, I still have tons of ideas for new SNPCs.