The Japanese Federation seems to have taken rather passive attitude towards their top female pair skaters, i.e., Ina, Inoue, & Kavaguti. To be honest, I do not have any knowledge as to whether there were any negotiations among federations.
I also have no idea if Japanese federation attempted to recruit the Shibs. I've watched the Shibs' FD video at the 2009 Junior Worlds. In that video, a Japanese commentator alluded how much they wanted the Shibs to represent Japan but was certain that the US federation would not let go of their promising young skaters. perhaps Doris might know the inside information?
Takahashi/Tran is an interesting case. For the first time, an internationally competitive team is representing Japan. They brought first Jr. World medal in 2010; they are also the reigning JGPF champion. We'll know just how competitive they could be at the senior circuit depending on their results at the 4CC & Worlds.
I hope T/T team does well. Perhaps it might be time for Japanese fans to start "draft Tran" movement?