Hi there. If you're about to send it now, stop and don't do it soon. Read the guides, as it seems like you haven't read them. Make sure you have all the forms, and they are updated. Use this link, it will give you the country specific requirements too:
http://www.cic.gc.ca/english/information/applications/spouse.asp#country
The checklist is supposed to be on top of the application. I am not sure if the barcodes pages go right underneath the checklist or on top of it, but the guides explain that. So yes, you have to send the checklist, otherwise your application will be returned. The visa office, or embassy, will request documents from you whenever they need them, there's not a specific when or on which time, but it would definitely be after your file is transferred from Canada to the visa office.
My advise to you is, take this very seriously. Do it right the first time, and you won't have to deal with returned applications or a delayed process. Take your time to do the homework and do your research, it is as simple as reading a couple of guides, and ask a few questions on the forum.
