According to 'Carroll Spinney' in his autobiography, he created the concept after working on Bob Hope on the Road to China (1979). But Spinney does not get a writing credit.
Xiao Foo's name in English translates to "Little Lotus."
When this was released on DVD, about one minute of footage was cut which involved Big Bird looking for someone who spoke "American" (meaning, of course, English, but he didn't know it was called that).
According to "I Am Big Bird: The Caroll Spinney Story", the filmmakers had an attachment to Ouyang Lianzi, who played Xiao Foo, and they bid her a tearful but restricted goodbye at their airport, and they never saw her again as much as they hoped. Her name in English is Lisa Ouyang.
According to 'Carroll Spinney' in his autobiography, he and Jon Stone did not get along during filming.