NIW RFE, two questions

Hello, Ge Wei Da Xia,

Please help, 2 questions about NIW I140 RFE.

1. What does the "priority date", or "as of the filing date of your petition" mean. I just got another 2 paper published after my original filing, does it mean that they won't count it?

2. Do I must use the enclosed envelope to mail all the materials, but the return envelope is really small, and how to put all the materials into such a small envelope? Can I use a big envelop and just attach the return
envelope?

Thank you very much