When Severian appears in Dr. Talos' play, it is interupted by a tableau which Talos uses to squeeze the audience for money. He calls special attention to certain scenes, telling the audience, "Remember that you have never as yet learned the identity of the mysterious figure seen by the Contessa through the curtained windows". We later learn in UotNS that the mysterious figure is Severian. But the Contessa Carina remains mysterious.
Using Rules of Names 1 and 2a. can provide some clues.
Rule 1. There does not appear to be a Saint Carina in the lists. However Carina is a constellation and the name of the ship Argo's keel. This might suggest her character is a non-human. Both she and the she-demon Jahi are played by Jolenta. Jahi's lip is split by Meschianne. The Contessa is smacked by Meschia. Later the Contessa is escorted along the Road Of Air to recover from some minor injury. Both Jahi and the Contessa are trying to become impregnated by Meschia on the last day of Urth.
In the similar scene in UotNS there are some suggestions that the crying woman Severian escorted on the Path of Air is his mother Catherine. Since the Path of Air might be a time travelling path back to the time of Severian's youth this could make sense. But Rule 2a. suggests that the name Carina (instead of being a Scandinavian alternate of Catherine) might denote a kaibit of Catherine.
Much of the speculation that time stands still in the Atrium of Time (despite the changing of seasons there) is connected to the idea that Catherine's appearance never seems to change for roughly 15 years. But if she has a kaibit, an alternate explanation for her eternal youth is presented which meshes better with the rest of the characters in the book who retain youth.
-bsharp