The more idiomatic way is to pass in the “compatible” module as an argument to Xs functions.

There is an idiom used when a library defines a module that must be instantiated by the application that uses it, along with some configuration.

Ecto.Repo is an example:

defmodule MyApp.Repo
  use Ecto.Repo, otp_app: MyApp
end

The otp_app keyword argument allows Ecto.Repo to lookup the remaining configuration with Application.get_env(app, __MODULE__)

In simpler cases the config can be passed directly into use.

You can pass module atom names around all you want and call them directly, so yes. (The OCaml Witness Pattern via First-Class modules)

If however you are refining a module based on another module (a limited form of OCaml Functors), Elixir/Erlang does have first-class support for that currently in the form of tuple-calls, however that feature is being broken soon much to my irritance… >.>