This doesn't answer the questions you listed, but if you are trying to create a strict 90.1-2010 Appendix G baseline building, here's what I'd suggest:
- It sounds like you have a nonresidential all-electric building that is less than 4 floors and less than 25,000ft2.
- Per Table G3.1.1A your baseline HVAC system is "System 4-PSZ-HP" (packaged single zone heat pump)
- Per G3.1.1: "For systems 1, 2, 3, and 4, each thermal block shall be modeled with its own HVAC system." So in this case you aren't creating a multizone system, you are creating a single zone system for each zone.
- To model this in OpenStudio, add one of the Packaged Rooftop Heat Pump template systems for each zone.
