I assume she did not get a re-entry permit. Physical address is where a person ACTUALLY is. Indicating anything else is playing with fire, imo. This is not a good time to be trying to play the immigration system, imho.
Have you thought about leaving Stepdaughter #3 off the I-751? Then, filing a separate I-751 for her? Perhaps a legal opinion from an immigration attorney might be helpful.
I am eager to see what other VJ members think about this situation.