Magenta Dress Pleats

You can easily incorporate pleats to any commercial shirt-dress pattern of your choice.  Draw three parallel lines directly on the pattern about an inch apart - I'd probably put the first line about 1¾" from the pattern's center front. 

Cut on the 3 lines you drew on your pattern and lay the pieces out carefully with about 5/8" gaps between the pieces.  Use the pattern's waist line to keep them lined up evenly because the shoulder and neck lines will appear uneven.  I recommend taping down the pieces once you have them arranged.  With a tracing wheel and transfer paper, mark the center of each gap from shoulder to hem.  This will be the line you fold your fabric on to stitch down your pleats.  Sew your pleats just over ¼", then press (away from center front).

I finish my edges with single fold bias tape.  I tuck the loops into the edge about 2" apart.  The buttons are sewn closer to the pleats than the edge.

Magenta's Dress Pleats (Research)

Because details are so hard to see on black, there aren't many places in the film where you can really see Magenta's pleats. There are 3 on her sleeve that appear to end before the shoulder seam, and 3 down each side of the front.

You can also see that her white collar isn't completely attached in front.
Also notice that her sleeve stops right above the elbow; longer than your average "short sleeve" dress.

Magenta Apron - Part 3

All that's left to do is to secure the straps in front, then adjust and secure the straps in back. Trim the excess length, fold the trimmed edge under 1/4" and stitch by hand to the waist band. 

 Remember to leave enough slack in the straps. I also recommend rigging the apron straps to secure to the shoulder of the dress with a small piece of color-coordinated velcro or small snaps.