I cannot help you much with any good advice on Elm, but regarding Elixir, the best bet for your money are the following options:
I really recommend buying both, read first the book and then watch the course, the latter will help you to think in Elixir.
Additionally, the 2nd version of Sasa’s book, Elixir in Action is also great.
As an additional advice, save the rest of your money if they are limited to buy Programming Phoenix ≥ 1.4 and Programming Ecto when they will be released.
Regarding, Elm, Programming Elm seems an interesting option, I highly value the quality of The Pragmatic Bookshelf.
