I think documents submission depends on the type of application.
I applied as FSW and submitted the required initial documents with the applications. I think the documents that were submitted for my family are birth certificate, transcript of records, diploma, income tax return, xerox copy of unexpire passport. When I received my AOR, they requested me to take IELTS and proof of relationship coz my wife has an uncle in Canada.
After initial assessment which took about 8 months, I submitted my employment reference letter, fbi/nbi clearance, income tax return for 2007 and proof of funds.
Also, we completed our medical on Sep. 04, 2008. Hope this helps.