There are all these great armor and weapons mods out, but most of them only seem to be available for the Player Character or followers you give them to. Is there an easy way to add them to leveled lists so that npcs will randomly be found to use them?

Open up the mod in the CK and add them to the leveled lists.

It's that easy? I wonder why more moders don't do that themselves.

because if 2 mods overwrite the same level list, only the last mod loaded will get to have their items appear. the one(s) lower in load order will have their edits completely ignored

level lists do not merge from multiple mods, they overwrite each other if they are accessing the same list

Ah, so it's not that simple. Can I just merge two or more mods if they don't conflict? There's a program called Wyre Bash that I think does this but I can never figure out how to make it work.