Welcome! this aligns with none of your goals, but I'm going to mention my own site as a resource anyway, as I'm also an artist using Linux. My site is
http://slackermedia.ml and it's all about making music and video and other things on Linux. It may be interesting to you.
Aside from that, the best way to learn BASH is to use it. Here's my humble resource about that ->
http://straightedgelinux.tk/unix/shell/?dir=unix
The pi as a webserver is really easy. Install Nginx, and go to the Pi's IP address. You're basically done; only thing after that is to figure out all the firewalls between your Pi and the rest of the world.
Linux from Scratch would be very educational. I also recommend Slackware which, in a way, skips over the "from Scratch" part and just dumps you into a text console so that you can configure your computer. It's pretty educational in itself.
Whatever path you choose, welcome to LQ and welcome to Linux!
