Almost a year later, a little update at last on how things are going!Though I haven't updated the ZIP file yet with these additional levels; I may or may not do so - the question is how useful a second "interim round" would be, or whether I should try to finish the whole pack first, and then send it around to testers.
There are about 40 levels left to go now, so around 80 are completed.As you can see, I've also changed some of the level titles, compared to the list I had originally compiled on page 1 of this thread. I'm trying to have a few more well-known songs in here, while still picking such that fit with the respective theme. In Lemmings, Drugs, & Rock 'n Roll, meanwhile, I have more freedom with regards to the titles I choose.
CIRCUS
Tears of a clownCLASSIC
The Well-Lempered Clavier
HIGHLAND"Sing me a song of a Lem that is gone..."
Skye float songMEDIEVAL
Heroes of our timeOUTDOORWho says stupid bee puns are reserved for the Honeycomb tileset?

Let it beePOLAR
Last of the wilds
Slider levels really make my pre-placed Builder staircases (from strato_generalmd) come in handy... ^^
Trapped under ice
SPACE
Faith of the heart
The dark side of the moon
SPORTS
Let's get physical