I can't recreate this issue either with or without externals. I'm not getting an error as yet, when does it occur?
What seems to be happening is that if you install the mod while other mods are already loading the required libraries, you won't get the errors - and this is also why loading all of those libraries separately, works. I actually get different missing library errors on each character with this mod, because they're all loading different sets of other mods, so I'm loading different sets of libraries too. I am no coder, and I'm sure there's a technical term for this, but it seems clear to me that this mod isn't referencing/loading its own included libraries, it is strictly looking outside of itself.
So, to re-create the problem: disable all other mods and libraries, everything. Load only this mod with the libraries as internals. Errors about missing libraries spew forth upon login.