Adelina Sotnikova confirmed this account like the real Nikita's account:
http://ask.fm/adelyasotnikova/answer/109605540019
Here Adelina wishes the best at Worlds and once again she posts this Nikita's account:
http://ask.fm/adelyasotnikova/answer/110897533107
She links to two different accounts?
Is May 31st the deadline for Russian pairs, or for the entire ISU?
Just for Russia. I'm not sure when the deadline for submitting skaters for grand prix events is though. If it's before May 31st they'd have to be settled before then if they want the spots they are entitled to as returning split couples.