This sounds like a great project. I would love MediaGoblin to be in Guix also.
> 6. Rewrite MediaGoblin's JavaScript code not to use jQuery. Maybe > improve the no-bundled-JavaScript video/audio playing experience. What are your thoughts on rewriting the jquery? Should MediaGoblin be using vanilla javascript instead? Some other possibilities could be purescript (https://www.purescript.org) or mint (http://mint-lang.com), although mint and crystal are not in guix yet and mint uses preact (http://preactjs.com) as its' runtime since 0.8.0 (https://www.mint-lang.com/blog/mint-0.8.0).