Apparently they are still giving reciprocal membership to C&A members, but only up to Elite level. I have 150 points under their new plan and am still Elite, but Elite starts at 300 points. Thus, if someone is Diamond Plus or Pinnacle Club they shouldn't expect to get Elite Plus or Zenith level unless they earn it through Celebrity.
This makes sense and aligns to what RCI does for Captain's Club members. So I'd expect that a Zenith member would still only get Diamond privileges on RCI. That is reasonable for both lines.