I heard it's this one below, featuring Haley Reinhart by Postmodern Jukebox, so it's likely the same one as what Marin used before.
I understand you like the original, but I don't hate this, either, and I wouldn't be surprised if Kana suggested it or if she had it on her playlist to pick from. Or rather, I would be more surprised if Rinka knew the original instead.

Is it soft and cutesy for you?
Edited to add:
Here is Rinka's interview
目次 CLOSE まだまだ伸びしろたくさんある 好きのベクトルがすごく大きくなった 渡辺倫果のラフマニノフを 渡辺のコメントは次の通り。 まだまだ伸びしろたくさんある ―新シーズンに向けて、現在の練習状況であったりコ […]
deepedgeplus.kyodonews.jp
from the part where it isn't paywalled
ショートの方は新しい自分というか、新しいニュアンス、テイストのものを、村元哉中さんだったり、林(祐輔)先生に選んでいただいて、この曲になりました
For the short program, I wanted something that would reveal a new side of myself—a fresh nuance or style—so I had Kana Muramoto and Coach Yusuke Hayashi help me select the music, and we ended up with this piece.