Well I got an interesting email today.
Dear (uranussama),
I hope this email finds you well. I am writing to let you know that you are still approved as an alternate candidate for MEXT. Should an accepted candidate back down, you will be upgraded and offered the position. You will remain an alternate until June of this year. Should you wish to be removed from the alternate list, please let me know at your earliest convenience. If you wish to remain on the alternate list for now, but need to back down for some reason between now and June, that is fine as well. Just let me know.
So whoever sent me that email last week mustve made a pretty big mistake. I knew it was too good to be true.