I think, if you want Tuesday as a first name, the middle should probably be something traditional and obviously feminine (to balance out the modern, gender-neutral first name).
Here are some ideas, off the top of my head:
Also, I would avoid middles that happen to be nouns (e.g. Grace, Ruby, Lily, Rose). Tuesday plus one of those could easily be turned into a joke, which would not be a lot of fun for little Tuesday.