So far, things are going reasonably well. Youngest Son is _very_ fond of their dog. I had to pull him aside a couple of times and explain that Jack (the dog) needed a break so he was going to have to find something to do besides chasing the dog all over the house.
My Beloved asked at one point of Youngest is always this active. I said "He's five. This is what five year olds do." She said "No it's not!" So I amended my statement: "This is what five year old boys do."
Oldest Son seemed kind of agitated about Jack. During meals Jack runs around under the table. Oldest found this very distressing. Willow doesn't run around under the table. She can't--she's taller than the table.
The two girls are on their best behavior and acting like guests rather than residents. I'm enjoying it for now and assuming that it won't last.