Yes correct, only the upstairs light is in a a 2 way configuration. the downstairs hall light and porch light are only 1 way.
A couple questions for the 2 way switch with the zbmini:
can the existing 2 way wiring not be reused or will I need an electrician for this?
can this be done with the zbmini in the upstairs wall switch, with one gang of the downstairs switch being wired to this for the two way configuration.
Yes correct, only the upstairs light is in a a 2 way configuration. the downstairs hall light and porch light are only 1 way.
A couple questions for the 2 way switch with the zbmini: