You're welcome, but all credit goes to ccexplore for the split Arc Lemmings and Oh No! More Lemmings .mods, Tsyu and Leo for the split-up Arc Lemmings 2 .mods, and to Valley Bell (not from here) for creating the MS-DOS Lemmings and Lemmings 3D VGM sets.
All I did was convert all of the music to .wav, and then trim and add fade-outs and opening and trailing silence to the Archimedes tunes, and add opening and trailing silence to the VGM recordings, before encoding them all to MP3 format.