Max,
Anyone that has all there documentation can marry (in theory straight off the plane) as and when they please, even us Brits lol!!. I was talking about those that are living there or spending an extended period of time there....
If you haven't got a a single certificate, then your not going to be able to be able to jump off the plane and marry!!! As i said above, in that case you need to be in the country for a minimum of 21 days to go the other route. I can't qualify the other 21 days, as your system maybe different, but i'm pretty sure some time lapse will be involved!!
David.....