Multifamily Setpoints and Equipment Load

No you are not required to use those values. That is just one of several potential sources for values to use or you can apply what you would expect to be applied to the design.

In my opinion the LEED Coach is incorrect. LEED Mid-Rise does require the use of these guidelines but LEED NC does not. It is a violation of the rules governing the development of LEED to include credit requirements that are not in the credit language. So those guidelines must be optional, just like the DES was optional under the previous version of LEED. If push came to shove I think you would easily win that argument and modeling a 78 degree cooling set point when your systems are designed for something much less is just ridiculous. If you want a clear, no reviewer questions asked, sort of response on this you should probably not rely on me or the Coach but submit a LEED Interpretation. Personally I might follow these guidelines where they make sense and ignore the ones that don't. If we were working on a multi-family project right now that is what I would do.