1) BackTrack is an OS, you only need to install a ettercap (a single program) on your Linux or Windows OS.
2) Yes, you can.
1) See below.
1) MITM tutorials are easy to find, just google it. Hint: ettercap.
1) You need to install Windows first. See kali forums for more info:
http://forums.kali.org
1) What about google it?
1) Using SSLstrip.
1) Use ettercap.
1) Scroll down to see your answer.
1) It is not a question about hacking (just search it).
1) If you are sniffing traffic standing in the middle, there is no reason to not get the password. Remember that facebook uses SSL (https), so you need to use a proper filter to get the traffic.