Page, I absolutely DO know.
Valerie Curtin played "Jenny", who later became Janet, in the first pilot.
Also in Pilot 1 was Susanne Zenor (not sure if it's Susanne or Suzanne) as "Samantha", who became Chrissy in Pilot 2. In Pilot 2, though, Chrissy's role was played by Susan Lanier.
Did you know that Pilot 1 was done by Larry "M*A*S*H" Gelbart?
Dane, you are most certainly welcome.