Guys as far as I know.
1. Yes, they requested another pictures which is in their emai attachment appendix B - photograph specification. It would be 6 pcs.
2. No, UCI is different from file number. As file number is the application number which consist with 1 capital letter and 9 numbers.
ex: E000135479
Thanks for this info!
Client ID Number / Unique Client Identifier
You will find this number, also referred to as a "Unique Client Identifier", on official documents issued to you from a Citizenship and Immigration Canada office, Case Processing Centre or visa office where you submitted your application. Your Client ID Number/Unique Client Identifier has four (4) numbers, a hyphen (-), and four (4) more numbers. (Example: 0000-0000).
Immigration File Number / Application Number
You will find this number, also referred to as an "Application Number", on any official document issued to you from the visa office where you submitted your application. Your Immigration File Number/Application Number starts with a letter and is followed by a combination of nine (9) numbers or letters. (Example: B000000000 or EP00000000).
check it here: https://services3.cic.gc.ca/ecas/redir.do?app=ecas&lang=en&redir=id_num