I think that all of the Junior Grand Slams winners/runner ups will be good.
I mean Townsend, Putintseva, Beck, Scmiedlova Bouchard, Svitolina, Crawford and Kontaveit would have to be a lot of people' best bets. Except for Vekic, Barty and Khromacheva I don't think there are any stars powering through except them. As for Sharipova, she has good game, but she has weak points, no head and bad movement
I still like her though
As for the Bouchard vs Svitolina thing, I think that Eugenie has more game but I think Elina will achieve more as she can play on all surfaces well as shown this year, whereas Bouchard is strictly Grass and Hard, not recording any amazing clay results