Here is the tutorial of the simple spring top, as promised. I made another version for my niece, but decided to leave the buttons off, since they were more decorative than functional (and because I didn't have enough fabric). Read more for the rest.
For this 4T top, I used the cut the following:
2 - 9" lengths of bias tape for shoulders
3" x 24" bodice and lining
8" x 34" bottom
34" bias tape for bottom
With 1/2" seams
Sew the shoulder bias tape shut along one long edge. For extra fanciness, top stitch other long edge as well.
Voila! Easy peasy lemon squeezie! Go outside and enjoy your very warm spring.