Hredux: Fat Buttery has been found!

My sister used to read mystery stories when we were little. One of them involved three orphan children as the main characters. They were a young, thin white girl who wears a red velvateen dress with a pinned on white collar, a native american boy of 7 or 8 and a toddler nicknamed "Fat Buttery" who, like many children that age, refuses to wear clothes. I remembered it again when Lemony Snickett released to the theaters. At long last, I stumbled on the right google keywords and timing: "Fat Buttery" indian book. The name of the story is Journey for Three by Isabelle Holland and was a Weekly Reader bookclub selection.

Thanks go to http://www.logan.com/loganberry/solved-l.html