It's really gorgeous!! and it looks identical to eggplant to me. Has Balenciaga ever officially said they NEVER repeat colors, because I think they do and just change the name.
We all know how colors vary from bag to bag, the only way to be sure would be to have several mint eggplants and compare them to several violets. Even then, the eggplants may have changed a little since it's been over 3 years.
I have eggplant and yours looks almost identical to my eggplant and I can't see any difference in the color of you eggplant wallet and the bag, only a vairation in the leather.
Anyway, your new Day is reallyyyyyyyyyyy gorgeous!!!! Congratulations!