I have changed cages 4 times and moved Congo to different locations over the past 25 years. I usually fill up 1 of his food dishes with lots of fresh veggies and goodies to eat to relieve his stress and it works. Usually within a few hours he adapt to the new surroundings.
As for your 12 year old. Let her be the "only 1" to feed Storm his favorite treats everyday. She needs to talk soothingly to Storm while giving him his treats. Storm will associate her with receiving his favorite treats and after 3 or more weeks will start to accept her. Eventually she will be able to slowly pet Storm yet she will still have to be aware of what mood Storm is in.
Now with dogs African Greys can be very funny. My Congo has outlived 2 of my dogs, I have 3 dogs now ranging from 50lb to a 2 year old Newfoundland that's 125lbs and still growing. When Congo was younger he would open the door to his cage and would purposely drop some food on the floor. When he noticed the dogs would eat whatever he dropped. Congo would do 1 of 2 things, sometimes Congo would wait outside the cage and try to grab the dogs hair as they raised their heads. I know my dogs are friendly and wouldn't bite Congo. They see Congo as a food giver and are always looking for treats from him. I wouldn't allow this if the dog had short hair or are unsure of how the dog would react. My dogs caught onto Congo quickly so they would back out without lifting their heads so Congo changed his tactics. Now after spilling some food on the floor he would rush back into his cage grab his water dish and would carry it to the front door flip it over on top of the dogs. It was just so funny to watch how intelligent Congo was and how he could trick the dogs into doing what he wanted. Eventually the dogs caught onto that and as soon as they hear Congo's water dish making noise they are out of their. I also have to laugh when Congo calls the dogs by name with either my voice or my wife's and they come running in looking at us then realizing that crazy bird is causing trouble again. Sometimes when I'm eating crackers with peanut butter (Congo's favorite) my 3 dogs are all sitting in front of me to get some. Congo comes out of his cage walks in between the dogs climbs up on me and waits for his piece. Yes, I give them all a little then when I'm finished they go back to whatever they were doing before.
Enjoy Storm eventually you will have many stories to tell.