Professional Engineer

There's no need to engage with a Professional Engineer to meet the prerequisite. Working with a Professional Engineer is only required to apply for the ENERGY STAR label/certification.

Now that process energy is considered, notably commercial kitchen equipment, including ice machines which are factored into prerequisites too, Appendix 3 in LEED V4 Retail has the accepted standards. Some of them call out Energy Star or 'performance equivalent", others have listed criteria. Ice machines, for instance, (located on hospital patient floors, hotel floors, athletic depts., etc.) aren not just in the kitchen and run all day. Indicating 'performance equivalent' is excellent because the Energy Star standard is for cubers and extruded ice makers use less energy than cubers.