Hello again, CajunBeauty.
Preppocalypse will load up the NPC Mod without any errors or warnings. In fact, Preppocalypse has its very own NPC helpers in the form of 'friendly zombies' with weapons just as with the hostile types added. Naturally, all of the other NPC Mod Add On Packs are all very welcome to fill up the environment, and add that extra sophistication.
This Add On Pack hasn't been added to the listings above, and possibly because it is not deemed an appropriate entry for the overall goals of custom made content.
Preppocalypse type NPC helpers can be download here though:
https://github.com/arramus/A21-NPCMod
And this particular one is the https://github.com/arramus/A21-NPCMod/blob/main/1-SummonFriendZ.zip
