I also never mentioned players.
This is getting off-topic. I have my answer, and anyone who stumbles upon this thread will have everything they need 
NPCs also have Characters with Humanoids, It’s just most people don’t use them for it’s intended purpose and end up making NPCs without Humanoids.
The more you know. It’d be nice for them to change this behavior to work locally as well. It baffles me how many features Roblox actually half implemented… But maybe NPCs weren’t really a thing in the beginning and turned out to be a bug turned future.
@Intended_Pun in case it helps you in the future. I generate my NPCs on the server and cache them in ReplicatedStorage. The client then checks ReplicatedStorage for the cached versions and make copies as needed to create them locally. This circumvents changes to Insert Service not working on the client, in the event that your NPCs needs to use the HumanoidDescription System.
Please don’t hurt me, I tried keeping this on topic as much as possible solely to respond to Nuclear 
I don’t see the phrase “NPC” once within the OP. Am I missing something?
My NPC part was in response to Intended_Puns statement as follows.
Since I figured he’s doing his Humanoids on the client, same as me. That he may one day try to use the HumanoidDescription System to apply an appearance easily on the Humanoid. Which as the time of this post doesn’t work on NPCs (unless somethings recently changed.)
I simply wanted to share with him that he could still spawn NPCs locally while spawning them on the server.
To answer your question tho, it was a reply I was talking about, not the OP, Since that was already solved… I didn’t see the need to try to solve it again. And since there’s a designated post marked as a solution. It didn’t feel that far off topic and could still be helpful to others.