Out of the 3, I'd say Rosie deserves it more, she's definitely in the most dire situation, at least when compared to the other 2, the order would be Rosie > Veronica > Felicia. Even the game itself recognizes this multiple times, when the carnations have talked between each other Vero and Rosie will gang up on Felicia for having a dumb reason to join (even thought they don't know her real end goal) and Ronnie will downplay her own situation when she compares to Rosalind's.
But I also think that downplaying the importance of each situation, or saying "who needs it more" is nonsense, because the game itself also tells you that for each of the girls, their problem is just as big as everyone else's, each one of them is their own person, and they have a lot at stake here, via it might be their livelihood or their dream.