Today, I was working on a much simpler version of this using api.customizeComposerText() 
This is a so much better solution. Thank you @awesomerobot!
In my experiments, I was never able to override the Composer button label for the categories using the discourse-post-voting plugin. This becomes a bigger issue when multiple categories are enabled for post voting.
If I may suggest; enabling support for overriding discourse-post-voting labels, would be a great enhancement. ( :