
For my costume, I'd like to do a waist along the lines of this pattern from Past Patterns. It's ten years out of style for 1907, but I'm an old maid, so it will work.
Butterick has pattern along similar lines. See Butterick 3417. Depending on how good a deal I can get on fabric, I may even make a skirt to match from Butterick 3418. Otherwise, I shall have to wear my Folkwear Walking Skirt.
For the other girls' costumes, I think I will use the same skirt pattern with variations. Rachael's waist should have a V neckline with an high-collared inset; Laura wants a square neckline, and Andrea wants something off the shoulder. I'm hoping to find some vintage evening gowns to tweak. I haven't found existing patterns for the girls' and I don't have time to draft draft patterns for each girl's dress.