The difference between 115 and 120 Music in your case is an additional 5% chance in Disco'ing and Provo. Not much at first glance but if you went through the pain taking the other two to 120 you're probably up to chase the big ones with 160 Barding Difficulty. If so, I would go for the scroll.
And about the other question... It depends on your strategy. If you cast a lot then 120 Medi could be an option - or Eval Int if you cast mainly offensive spells. Anyhow, I would raise Music first. (This is the Bard Forum. What do you expect?

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