I am also not a mod creator, but, since I do some programming maybe I will get my hands dirty at some point However, at the moment, I am dealing with a lot of other stuff, trying to configure a modpack to my own taste so creating a mod will come a bit later down the line. For now, if anyone stumbles on this topic and is happy to create a mod for this I believe it would help modpack makers to consider Custom NPCs in their packs.