[...] Morwen IC has an instrument [...]
Three now, actually - that she actively plays, anyway - I have a little 'fluff' interview/article about this that I've almost got finished, but the tl;dr is that 13 years of training in performing arts and little else (like a little help from a source she usually keeps quiet about in public) has left her comfortable picking up most stringed instruments and figuring them out within a few weeks or months. Then there's dancing and vocal training, as some have experienced.
Sakaane is another character who sings and plays a couple instruments, and it's a big part of her character's backstory.
I think it's a good way to provide character-based content for the entertainment of other players (and their characters, of course). As far as recognition goes, it's the same rule of thumb as with other kinds of things - the more 'local' you keep your sphere of influence, the better, because the number of people affected by it stays limited and allows for more opt-in. If they've heard of the group, awesome. If not, well, they just weren't around in the right place(s) at the right time(s), too bad. For example, Morwen and Anabella (from EM) might have heard of Anslo's group, both of them having grown up in Caille, but on the other hand, if the style of music played by that group wasn't to their tastes, they might not have - no harm, no foul either way.
Claiming very widespread recognition is probably pushing it, though - but I can't think of any cases where that's been done. (Will post more later, I think - it's an interesting subject but I need lunch bad. :x )
