The new girl is surprisingly easy to defeat, though that may just be because I'm level 8. I just smacked her with my fire sword repeatedly. I'm a bit embarrassed to say that I completely forgot about the grab block mechanic till I went back down to the first floor to try and see if I could beat everyone's Level 3 fights, what I'm not embarrassed about is me breezing through all the QTE's of the grabs and still kicking her ass while going through all the choices to see what I may have missed.
At Level 8, you can reliably beat everyone's Level 3 fights, with the 2nd floor being easiest due to fire punches, followed by the Water nun, followed by the new girl and surprisingly, the 1st floor is toughest solely due to her elemental affinity.