@Wayne ******
I may be misunderstanding you, but are you saying that one doesn't have to prove the funds for the marriage visa are from overseas, whereas they do with the retirement visa?
As for the documents required, I'm aware that immigration offices in the different provinces have some slight variations, depending on what you need to get done. I have seen mention by expats that some of the documents that are exactly the same each year and don't need to be dated and signed each year or things that Stephen mentioned, they just use again, or make copies and use again the next year. I've not seen mention of the specific documents though.