1) I think it would make more sense in Level Select for the "Xmas Lemmings" subgroup to be renamed to "Holiday Lemmings" and for the "New Year Lemmings..." collection to be moved inside this subgroup in addition to the "Holiday Lemmings 1993 & 1994" and "Xmas Lemmings 91 & 92" collections.
Yes, good idea. I'll make this change in the next major update (2.8).
2) In the "Covox Lemmings" collection there are only two levels per difficulty, whereas in the SupperLemminiToo "Save the Lemmings" collection there are six levels per difficulty. Would it be possible please to add these levels into SuperLemmix in a future release?
The levels you're referring to are part of the Prima Publishing pack, which is included in the DMA Lemmings compilation. In SLToo, these levels were combined with the Covox ones to make "Save The Lemmings".
I'd be happy to update the compilation to gather the more incidental bonus levels such as these together in one place. So, for example, we could combine Prima, Covox and the Bonus ranks from
Lemmings and
Oh No! More Lemmings all together into one mini-pack within the DMA compilation.
Do people think this is a good idea? Or, would people prefer for these levels to remain separately grouped?