Ah, if only I had a DS... Nice work.
I see, though, that your count of included levels is still counting the second two from XMas 91, which are direct dupes from ONML...
Have you considered also including the levels from Covox Lemmings, and the Lemmings Companion bonus disk? Okay, so they wouldn't exactly be a major addition to the level set (8 in Covox, 16 in Companion), but they are, as far as I'm aware, official...
Might also be a good idea to consider including the 100 (or so) levels which were unique to the Genesis/MegaDrive version. ccexplore worked out a way to extract them...
one last thought before clicking 'Post': "Going their separate ways"? "Ohayo Lemming-san"? The anti-special (Amiga Budget) levels? the Sega levels from MasterSystem Lemmings?