I'm mistaken, there were some songs missing at launch. It appears the release schedule for those songs was as follows:
Shield of Song - November 2000 era
Niv's - February 2000 era
Solon's Bravura - April 2000
Jonthan's Provocation - April 2000
Thanks to
millers for pointing that out.
Related spreadsheet is here if you are interested:
https://docs.google.com/spreadsheets...fSY/edit#gid=0