There - see, it can be done- an attached back cape over a back invisible zipper, without velcro or snaps.
A plea to the Disney costume designers: you know your amazing princess frock that's a triumph of animation? Well, guess what? Millions of seamstress mothers from all corners of the galaxy will be forced to replicate that outfit for their small daughters for Halloween. And while Elsa might have magicked her dress out of thin air with wishful thinking and glitter dust, we lowly human peasants are obliged to use real fabric, prickly trims, zippers and, you know, our actual brains. So might I plead on behalf of beleaguered craftyparents everywhere: would you guys consider, for your next princess movie, having your intrepid heroine don. . . I dunno, a plain Target Tshirt sewn onto a gathered skirt made with calico cotton? And feel free to add freezer-paper stenciled hearts on the front if it really needs to be ballroom-ready fancy.
[Kneads temples wearily.]
Anyway, here's where I am after two days:
I'd say it's 85% finished. It needs a hem job and some painted snowflakes on the sleeves and cape. And maybe something right in the center of that sweetheart bustier overlay. But otherwise, I don't need to fiddle with it any further.
And I can move on to Emily's Before-After lab coat. We're planning to make it reversible - one side pristine white and the other side covered in deadly radioactive sludge waste splotches.