Whoa! I had wondered recently if anyone could tackle Preview Harvey, and Yacko's so good at characterizations. Highest hopes for that one.
As for Bernice, we (my boss, actually) had our own real secretary Bernice back in those very years (mid-1970s) in the Hills of Beverly, and that's exactly how I picture her. This Bernice was more quite and demure, but the Eve Arden voice would still be perfect.