I think it depends on two things about Ayanna: (a) the range, quality and reliability of her jump shot; and (b) the speed with which she picks up the UConn system and the decision-making that goes with it. Those are the areas where I think Caroline has an edge, perhaps a decided edge.
But when it comes to a comparison of pure athleticism, Ayanna appears to me to be bigger, faster, slightly stronger, and a better leaper. I am guessing that she will be more of a rebounding presence than Caroline.
Even if Ayanna starts, I would expect Caroline to get major minutes, and for the two of them to essentially split the minutes at the wing position. I would expect the same if Caroline is the starter. Geno will go with whoever is playing better on that particular day.
Another possibility is for Caroline to start and play most of the minutes on the wing (with some time for Aubrey), and for Ayanna to join the scrum in the paint, where Dorka / Aaliyah / Ice / Amari are already competing for minutes.
If rebounding is a problem, I can imagine Dorka, Amari, and Caroline sitting while Aaliyah / Ice / Ayanna get the big minutes, even though none of them is over 6-3. Then the front court will look like 2002, when Swin / Asjha / Tamika were the UConn front court despite none of them being as tall as one might prefer.