Maybe Takahashi can skate for Canada.
For Narumi to represent and skate for Canada at the Olympics, it simply means she has to give up her Japanese citizenship because Japan does not allow 'duel citizenships'.
Yuko did that years ago. Even for Yuko, who seemed to have a decent chance on the podium at Vancouver as the Russia's No.1 pair team, she needed certain time to consider and weigh it with her family: whether it would have been worthy to give up her Japanese citizenship for the opportunity to compete at the Olympics.
I feel a small pain in my heart everytime I see her name as Yuko 'Kavaguchi', instead of her original family name 'Kawaguchi', to reflect more in Russian pronunciation. She sacrificed so much just to compete at the Olympics: her Japanese passport, her family name, learning Russian language, adjusting her way of living and/or sense of values to be more Russian way.
I would think it must be a bit easier for Mervin to get Japanese citizenship, if only both Mervin and JSF will go all for it and plead the government for a special treatment to relax (=lower) its requirements in his case.
I remember Rugby National team had 10 players who were originally non Japanese to compete for the Rugby World Cup 2011 in New Zealand, and five of them were registered as the naturalized Japanese citizens.
Other example I can think of is Sumo. We have many Sumo wrestlers who were originally born in Mongolia, and are now officially naturalized Japanese. I do not believe all of these rugby players and sumo wrestlers actually filled in all the requirements, such as to speak perfect Japanese and/or write decent Japanese. With the strong back-up by its federation, there must be some exceptions applicable for a sport, maybe?