I think it unlikely...
Wakaba can still make the final if she wins in Croatia this week. I think Sakhanovich is probably the only one who can stop her, but she was far from her best form last week, and has little time to recover... whereas Wakaba has had time to regain her form, and is succeeding based on her regional results in Japan.
So I think Wakaba has a good chance to reach the final - and if she does, and her form continues to improve... I think she will have a better chance of getting on the podium there, than Yura.
I am also rooting for Marin to get on the podium in Croatia this week, because then she will reach the Grand Prix Final too. Not that I really want to see Kaori Sakamoto get pushed out (or Alisa Feduchkina for that matter. There just aren't enough places at the JGPF!)
Whatever happens, it looks like there will be at least three Japanese ladies at the Junior Grand Prix Final, although which three is not certain yet. And it could be four if Wakaba wins this week and Marin gets on the podium too...