I like Ethel and Lucy! The "I Love Lucy" theme is great.
I'm partial to "people names", especially rarer ones or futuristic ones (but that's just the writer I am coming through.)
Some I can think of off the top of my head are Myra, Lexi, Eliza, Ellaluna, Beatrice, Maribel, Evelyn, and Clarissa.
I also like Nyx, Nova, Terra, and Luna.
You could also give them names based on their color or personality.
Like Sunny, Daffodil, Dandelion, Daisy, Sunshine, Blaze, Pumpkin, Lemon, Custard, or Dawn.