OK, This is interesting! I can't even begin to imagine anyone else playing Fred and Ethel Mertz but they weren't even close to Lucy and Desi's first choice for the roles. The whole I Love Lucy concept was based off of the radio show, My Favorite Husband, that Lucy had done for CBS radio fro 1948 thru 1951 (**FACTOID: Jess Oppenheimer, Bob Carroll and Madelyn Pugh all worked on the hit radio show with Lucy and then went on to I Love Lucy with her**)
Gale Gordon (Mr. Mooney from Here's Lucy) and Bea Benaderet (Kate from Petticoat Junction) were the two actors who Lucy wanted to plat Fred and Ethel but they were both contractually obligated to other shows, Gordon to Our Miss Brooks - another Desi-lu production and Benaderet to the Burns and Allen Show.
We can thank Desi for finding our Ethel for us. On the advise of director Marc Daniels, Desi went to see Vivian Vance in a play she was appearing in (The Voice of the Turtle) and hired her without even checking it with Lucy but the two became fast friends and soon realized they had a natural chemistry and their work together was an amazing pairing.
Sadly, the same cannot be said of the pairing of Viv and Bill Frawley. Bill actually asked for the role of Fred. He had a great resume, was a talented actor but their were rumors about some problems with alcohol that Desi didn't want clouding his show. Desi had a talk with Bill and told him he never wanted to see any alcohol on the set, Bill said that would never be a problem and he was hired. Bill was true to his word and turned out performances that to this day are unforgettable.
Bill got along great with Lucy and Desi but relations with Vivian were strained ever since he overheard her making a comment to Lucy about playing the part of a women being married to man old enough to be her father. The tension between them never eased from that point on and in fact, only worsened. It got so bad, Viv even refused to do a spin-off series about the Mertzes when I Love Lucy ended because the thought of working with Bill without Lucy and Desi as a buffer was too stressful for her to think about.
But, there you have the most unforgettable foursome in television history. Any comments, suggestions, memories are always welcome.