In the end, I just kind of did my own thing. Instead of making a pocket for the long ties, I made a casing and added elastic. Making the neck line stretchy, and adding straps that tie at the top. I used the same fabric from the ties to make a contrasting band at the bottom of the dress, just for a little added detail.
The nice thing about this dress is that it will fit her for a long time and she liked it!