Hi Cary,
1 - You should be able to do this if you select a font that contains the music note as one of the characters (see the "Show Character Viewer" in OSX input prefs for more info).
2 - You can't do this in DVDSP's subtitles editor or using plain STL files, but if you use more powerful subtitling software like CPC's MacCaption and export STL + TIFs, then you have much more creative freedom for how the subtitles are positioned (including split lines and multiple layers if you wish).
Hope this helps,
Jason Livingston
CPC Closed Captioning