I like Josephine Dell the best of the three (there are so many nicknames for Josephine!). However I agree with smismar and I like Vivian Dell. I also like the spelling Vivian the best and it may just be me but I pronounce Vivian and Vivienne differently with more emphasis on the -enne in Vivienne so that might be something to consider.
Emmylou! I wanted this name for my daughter due any day but my hubby didnt like it. It's such a sweet and tender name <3
Wow, we have really similar taste. I too am expecting a baby girl and have always loved Josephine but I've heard it popping up a bit lately. I also love Emmeline Louise and shortening to Emmylou or just Emme. Love that it is sophisticated but can be shortened to something young and sweet.
I also have Vivienne on my list, I prefer it to the other spelling of Vivian and would use the nickname Vivie. Again, a sophisticated, graceful name with a cute shortening.
My other option is Elizabeth Mae, shortening to Betsy Mae or Elizabeth Louise, shortening to Libby Lou.
Good luck, I think all your choices are lovely.