1. grep is all you need for question 1
grep yourawesomepassword wpa.txt (add " > output.txt" if you want results in a file)
2. I've heard good things about ultraedit
3. grep can sort out words starting with a certain pattern
grep -w BA
Suggested reading: man cat, man grep, http://www.backtrack-linux.org/forum...ing-guide.html




