Advanced metering for cooling and ventilation

You can often separate cooling energy use and fan energy use through the BAS. If you set up the BAS to monitor the fan operation you can calculate energy use from that data. That said I think that if they are both in the same unit LEED would allow you to meter the whole piece of equipment and not require that you separate them.

The numerous editions of the v4.1 reference guides over the years all seem to state "there is not substantive changes to the credit requirements, refer to the LEED v4 reference guide."

The v4 reference guide allows metering of one unit (e.g. Rooftop unit, heat pump, furnace, etc..) as an acceptable way to achieve the credit. Read through the FURTHER EXPLANATIONS - Determining Major Energy End Uses section, it gives pretty detailed guidance in this situation. 

This is not one of my typical credits, but I have had success with GBCI reviews when project teams submeter each energy source (e.g. gas & electricity) to each single packaged equipment such as a rooftop unit.