Well, I finally finished this up. Thanks goes out to pageturner19088 for advising me on the cardstock method, as well as using some of Twilight’s mane to add to her bangs.
Twilight: Got her bangs mostly closer to her head through a combination of the cardstock method and hair gel. Lost the natural, fluffy look, but I think it looks marginally better. The mane still refused to stay closer to her neck, but that’s okay because I want the scarf in there anyway. Gelled up the mane to keep it from separating too much, though. If I were to redo her with a fresh toy, I’d definitely have to be more zealous about pulling and securing the hair before I cut it.
Fluttershy: This initially looked like a simple job. Boy was I wrong. Getting her out of the package was almost a task in and of itself because Hasbro decided it would be funny to tape every piece of her hair to as much of the package as possible. So she came out of the box with her hair looking like she’d been hit by a lightning bolt. Used the cardstock method, plus wrapped her long hair right around her body and it worked almost perfectly on the roots. Had to do a second boil perm after I cut her hair, though, because it was took straight. Used straws to get the curls I needed. Her right side of her mane still didn’t turn out great, but I’m not sure how that could be fixed. Oh and I spent a few hours dealing with the stupid (what I’m told is) celophane in her hair. It doesn’t not respond to boil perms. It does not respond to hair gel (very well, anyway, it kind of works). Basically it made my careful styling still look like Pinkie Pie had rubbed a bunch of balloons on her head. I finally got frusterated enough to take a pair of siscors and clip out 90% of each piece of celophane. Boy was that ever fun.

All you need are some bunnies and snakes.