I read that the producers and creative team decided that Celia Keenan Bolger seemed too young for the part, and it was very important for Clara to appear older but have mannerisms and characteristics which gave away younger stages of development. Celia, who looked young in the part, seemed like a younger character and made the contrast confusing. And Kelli (who has a more mature look, and had been part of the cast out of town) was asked to audition for the part of Clara.
I'd love to hear Celia singing the songs from the show! Love both actresses :)
people on broadwayworld.com can be rude and scary