That's a good fix, by the way. You could also add the red army fleeing from Isabel in C3M5.I checked if all the Lords' artifacts appear in the original campaign, and yes, they all appear in the shops/buildings. It just seemed different before for some reason.
Added 8 minutes ago
Another thought: what about moving artifacts with red names? How bad of an idea is that?
Added 2 minutes ago
By the way, I just took SmallSpecialArena_Grass_Custom from the original, updated the file date to replace the ToE version, and everything is fine.