I moved this thread into a more appropriate section. Not sure if I should put this in the Event Help section...
Yes, ranking rewards are unrelated. Like Washu mentioned, you may have somehow mixed that up.
Regarding actually getting the early completion prizes, you're all not alone~ Many people, myself included, have not received the prize, while there has been a mention that other mates have. Don't stress too much over it, though. If it persists for days longer, send GREE a ticket with your concerns. You'll probably see when others who have not gotten it finally do at the
end of the event thread.