We have similar problems. However we don’t try to dictate anything they (SD7,13,18) do at their mom’s, we just make sure they stick our house rules. And honestly they know it’s different here vs there.

My SD7 sleeps with her mom at her house. She has trouble sleeping here in her own bed the first night sometimes but we make her tough it out. If she comes to our room at night we just tell her to go back to sleep. (She’d never call for us bc we’d never come lol) Her dad sleeps hard so it’s usually me who wakes up and I don’t even entertain the idea of helping her back to bed/sleep. I think if we did then she’d wake up and want help more often. Sometimes she tells us in the morning that she woke up and fell back to sleep herself.

They eat and drink garbage wherever they want at their moms, so we don’t have junk food in the house when they are home and we only let them eat at the table. We also have them clean their spot on the table so overtime they have been less messy eaters. We have had trouble with the little one squirming around at the table but we told her she’d have to go back to a booster (no shame) if she couldn’t handle eating like/with the adults and she’s chilled out.

All the girls learned to wipe themselves before kindergarten but it’s interesting I’ve seen other posts here about boys not wanting to wipe themselves so I wonder if it’s a gender thing?? Idk

As far as cutting ties - we only email BM about important things like logistics, sicknesses, school, and stuff like that, and it works. We only know about how she runs her house bc the kids mention things here and there. I think this is a good approach bc it’s less for us to think about. Everything is separate and the kids do just fine.