I don't know, I can definitely imagine a slightly more mellow version of Jenna and a slightly more wild version of Liz. I mean, you'd think that Jenna wasn't always so neurotic, that it increased when she got "famous" because once she got the attention she always wanted, she hated loosing it and would do anything to keep it, hence the neurosis. And we do know that originally, Liz as well as Jenna wanted to be an actress, so while still being a complete and utter nerd, I can imagine her being a little more outgoing than she is now.