Answers are based on my parents B2 extension. Unfortunately, there extension was denied in Jan 2008. The denial said extension material did not show the necessity why they need another 6 months to stay. We submitted our application in California center. However, our friend who lives in Atlanta, they successfully got their parents B2 extension earlier this year. Do not know which center they submitted, but definitely not to California center.
1) We submitted copied I-94.
2) We checked our lawyer and she said the multiple enties visa works even your extension is denied. Extension denial does not equal to denial of visa application.
3) We mailed our applciation 60 days before expiration.
4) 老弟在給爸媽辦澳洲移民,這在延期申請信裏要講嗎? 會有幫助嗎? No reference for it.
Good luck.