All three are lovely choices but I would rate them as follows:
1 [name_f]Rosalie[/name_f] - its sweet vintage charm is too beautiful to pass up!
2 [name_f]Daphne[/name_f] - a more unusual choice with sister [name_f]Amelia[/name_f]
3 [name_f]Eloise[/name_f] - it shares an “el” sound with [name_f]Amelia[/name_f] so it’s No# 3
[name_f]Rosalie[/name_f] - I like it. Sounds the best with [name_f]Amelia[/name_f].
[name_f]Eloise[/name_f] - Least favorite
[name_f]Daphne[/name_f] - I like it but I don’t think it’s compliments [name_f]Amelia[/name_f] as well as [name_f]Rosalie[/name_f] (if that matters).
Well, after reading all your comments and talking some more with my husband, I believe we have a winner: [name_f]Rosalie[/name_f]! Simply because out of the three names, it’s the one my husband likes the most. As for me, I love them all for different reasons, and I think I’ll still keep them in my back pocket just in case [name_f]Rosalie[/name_f] doesn’t feel right when we meet her, but for now that’s it, we finally have our #1 name, yay! 
Thank you all for your help, you’ve been great and very insightful.