I agree FarNorth I could have kept on top of the housework for the last 30 years if I hadn't had children going around undoing what I had just done and my DS still doing it at nearly 18! He should have got the duster out while they were together.
As for the potty training, if someone else's children came to mine, like DGC, I probably would have had them in nappies while with me, not only for accidents at my house but also so that they did not get upset if they did do an accident if they were engrossed in something we were doing. Your DD has all the summer to get both children trained so I wouldn't worry too much. It's not that big a deal really in my opinion. I would worry about far bigger things than this as they grow up.
NHS U turn on trans terminology