“We told the first AO that his school was “very, very high on our list”, which is true”
This is all you say, IMO. I don’t think you need to delineate a favorite. Repeat the statement above to any school trying to feel you out. Yes, it is encouraging to get the correspondence but don’t count your chickens before they hatch. Over the years, I’ve seen families surprised and disappointed by waitlists and rejections when they thought they had encouraging signals from schools. It is so soon after the deadline that they are still very much in the process of reading through all the applications.
Each school cares about yield. They play their angles, you play yours buy repeating the statement above. It’s not being untruthful as you and your child would truly be happy at all the schools you to which she applied.
Best wishes!