So we ran out of Easy-Ups today and put Chloë back in underwear.
Ohmigod this day has gone so much better than I thought it would.
She hated the idea, of course. The last Easy-Up was a dirty one right after she got home from a sleepover at Memaw's, and after that she was eventually persuaded to put on some underwear. She woke up from her nap calling "I have to pee! I need a diaper on!" but we refused, and after a period of wrangling she said "The pee is coming right now!" I pulled off her underwear and transferred her bodily to the potty, over her crying, and held her while she finished peeing. There was a mess on the floor, but she'd gotten some into the potty, and so we celebrated and cleaned up the mess for her and awarded her a sparkly moon sticker, which she was very pleased to get.
She got wiped up and into new clothes and underwear. The next time she needed to pee she said, "I need you to help me," which turned out to mean putting her on the potty and holding her. She was too agitated to go, then and later (which was in the middle of a session with the new arch sprinkler, during which she slid down the slide through the arch and onto a towel I put on the ground to prevent big bumps, to her delight). But after that she again said she needed to go, and I helped her sit on the potty and held her tight, and we were both rewarded by the sound of tinkling.
She finished, and wiped herself, and washed her hands, and grinned ear to ear as we praised and hugged her and got her another sticker and the promise of some gummy bears. She was by no means cured; she refused to sit on the potty to try to pee before bedtime, and chanted after dinner "I don't like underwear I only like Pull-Ups I don't want underwear today or tomorrow or the day after that or the day after that or the day after that or the day after that or the day after that or the day after that," and said plaintively on the way to bath, "I really wish we had more diapers." She's currently asleep in underwear, and we'll see whether she wakes up in the night to pee, as she sometimes does, or if I'll have to deal with a wet bed in the morning. I told her that if she does wake up she needs to go right to the bathroom when she calls me, and I'll meet her there.
But I see hope. It's good to think that maybe my oldest girl will be potty-trained before my youngest.