Thanks guys! For now, my workaround was to use Webpack to compile all my scripts into one, and then inject that one script inline using this command inside of a template file:
<script>
<%= compilation.assets['main.js'].source() %>
</script>
and the same for SCSS. I turned it into a boilerplate in case anyone else needs it, and wrote more about it here: Discourse-webpack: A boilerplate for developing JS-heavy Discourse components
https://github.com/BrowseHandsfree/discourse-webpack
I organized it in anticipation of making it work seamlessly with the Theme CLI (that’ll be ready in a week or so). My vision with this is to build some components with Vue/React locally and see them pop up live on the Theme Creator!