(Following the example of our friend Jina Chan, we'd long ago gotten a toilet seat that has an adult seat, a kid seat, and a lid all in one unit, and while at home she mostly uses the toilet now)
It went really well. Sunday night she even pooped in the potty, and Monday morning she wore underwear all morning with no accidents, despite the happy distraction of having a playgroup full of moms and kids at the house.
Tuesday she did pretty well at preschool in the morning, with one accident and one peeing in the potty. Wednesday out at the park with me, she unloaded all the poop she held in on Tuesday, mostly in a potty (I get the impression it's harder to detect "need to poop" and then hold it than it is for pee). This morning she stayed dry at preschool, too.
So she's doing really great. She's also still really fighting any attempt to put a diaper on her.
The stuff we've read has all recommended continuing with the diaper during naps and at night. But after 4 days of dry naps, I let Rosie nap with no diaper yesterday, and that went fine, so she's napping with no diaper on again today. 3 out of five of the past few nights she has also gotten up with a dry diaper (that happened a bit last week too, but I didn't keep count until Saturday), and is more likely to wake up dry when she fights us and is reminded that she has to go a week with dry nighttime diapers in order to not wear one at night.
(She also no longer wants to go on the changing table, but is more willing to put on a nighttime diaper on the floor).
What should we do?
Everybody says learning to stay dry overnight is a different thing than during the day, but that doesn't intrinsically mean you can't learn both skills at once. She seems determined. But she also woke up in the middle of the night Tuesday night and was up for two hours & on the potty 3 times in that time (she was also thirsty and very hungry though, and we also have seen other signs she's hitting a growth spurt, which tends to disrupt sleep).
She doesn't currently sleep with a nightlight, but there's one in her room. We could leave it on with a potty in there. Or, we could set the 'one week of dry mornings earns no nighttime diaper' rule, and if she makes it, we try without diaper. But then what's our rule about backsliding?
This is all pretty new to us.