And interestingly, because Yvonne De Carlo was a big movie starlet at the time, both Fred Gwynne and Al Lewis were apprehensive about the producers bringing her in to replace Joan Marshall after the pilot, because they figured she'd probably be a diva who'd make the production a dread for everyone else because she felt doing a television series would be beneath her (as was the mindset of a lot of movie stars back then, hence why the series adaptation of M*A*S*H didn't have any of the actors from the movie reprising their roles, except for Gary Burghoff because he was still relatively unknown at the time).
Joan Marshall (as Phoebe instead of Lily) had no personality, and her performance was bland and wooden, not to mention the character looked too similar to Morticia Addams (but Joan sure did have really beautiful eyes); likewise, Happy Derman as Eddie in the pilot was anything but Happy: Eddie was a lot more feral and an obnoxious brat.
And of course, thanks to STREET GANG, we all know that Beverly Owen getting herself fired from the show was all a ploy she and future hubby Jon Stone cooked up so she could be let go from her contract, freeing her to relocate to New York.