You could in theory do the MEP and IR before the CPL, but most instructors will probably suggest that this is a big step up and may be a challenge flying to IR standards without the practice of the CPL course.
Many have done it this way with no problems for years. It works out cheaper these days to do the IR first then do the CPL.
If you do the CPL in the twin you don't have to muck about with PFL's or glide approaches.