According to an interview with Big Love's co-creator Will Scheffer, they had to recast Teenie because of her growth spurt:
"But unfortunately our Teenie [Jolean Wejbe] — our cute little pixie — just shot up. By the time she was 13 playing 11, she started to become tall and looked like she was turning into a 15-year-old. So what we decided to do was recast.
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her age had nothing to do with it. people age on the show. its common knowledge that girls mature rapidly at that age. the problem was she didnt resemble anyone in the family. she had some "mulotto" features like my wife does. someone who is half white and half black. i dont know if she is, but my insider who works for tom hanks production company, which produces Big Love, said she didn't look "natural" in that setting-----chris
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them