I see the inspiration. :3 I've done group roleplay for 5 years here on Gaia, and two of those years I also did IM roleplay with my school friends. If you want, we could get together somewhere, like some sort of chat or something and I could help you set the idea up. I don't have much free time, but I do have my ways. This is being typed on mobile for example. :3
Well, I'm in a band guild, but I need to get out of it, its inactive. Need to find a new one actually. But basically, you just need to use the forums (probably Barton Town is your best bet, my old dead roleplay died because it was mixed with chatterbox mess) and just hope for the best. Forum rps aren't the best, but its a start. Maybe a guild could be made eventually.
I really love the music element, I think its a good idea. But I'm also not the general public on this, I'm biased to music programs. I'm in band myself. But supernatural roleplays almost never focus on music programs. I think if you get it out on a more public scale than a guild at first, it'll go well. Maybe try asking if there are any roleplayers in a music community. I plan on putting all kinds of activities into Yukashima Academy, music included. Maybe even find actual musicians and record a piece or two over the Internet. It'll take a lot of file compilation and audio editing, but it might be worth it.