Hello. I improved your CJM file for THEC64 and THEC64 Mini:
T:Lemmings Reloaded A:Lunatic Labs X:64,driveicon,fullheight J:1M: J:2:JU,JD,JL,JR,JF,JF,P,S,,RS,,,,,
It works with THEMouse and most other simple USB Mouses.
Tested with firmware version v1.6