I am curious if necromancers could, in fact, command multiple zombies/risen at the same time. I understand for playability reasons this not true. But as an idea for interacting with the wider NPC world, is this possible?

Almost every villain GMNPC necromancer has commanded hordes of undead. Lyras commanded an undead army and multiple risen. Did she have several acolyte necromancers (unseen) serving under her to create and command her legions? Was it merely a measure of the power of these NPC necromancers? Or do we assume it was the Hunger or another demon ultimately in control and the undead just mindlessly enacted Their will?

I understand that players will never really reach the level of power of NPC necromancers, but could it be reasonable to assume that my dozens of risen can be active in the world at the same time performing a variety of mundane tasks?

This is merely an expansion on Yvela's submission for the Magical Symposium involving constructs.
https://elanthipedia.play.net/Magic_Symposium

-N