Princess Fiona is primarily based on the classic fairy tale trope of a princess in distress, but with a modern and humorous twist in the Shrek franchise.
Shrek is an ogre living alone in his swamp. One day, his swamp is filled with fairy - tale creatures by Lord Farquaad. To get his swamp back, Shrek makes a deal with Farquaad to rescue Princess Fiona from the dragon - guarded castle. Shrek and his talkative donkey companion set off on this journey. When they reach the castle, Shrek battles the dragon and rescues Fiona. But Fiona has a secret - she is cursed and turns into an ogre at night. Along the journey back, Shrek and Fiona start to fall in love. However, Fiona initially believes she is supposed to be with Farquaad. When they finally reach Farquaad, he is disgusted by Fiona's ogre form at the wedding. Shrek then realizes his love for Fiona and they get married and live happily ever after as ogres in the swamp.
Adventure is also common. They might go on quests or travels together, exploring new places and having exciting experiences. For example, they could be on a treasure hunt or journey to a mysterious land. This allows for the development of their relationship and the discovery of new aspects of their personalities.
Friendship is a very common theme. Since they are from different backgrounds, their coming together and forming a bond is often explored. For example, in many fanfictions, they start as strangers and end up as best friends.
Fiona Goode is a powerful witch in 'American Horror Story'. She is a complex character with a lot of ambition and a dark side. She often uses her powers for her own gain and is involved in many power struggles within the coven.
Since I have no information about Fiona Kelsey, it could be that she has had a life full of different chapters. She might have started from a small town, worked hard in her studies to achieve her dreams. Perhaps she had some interesting travels that changed her perspective on life. There could be relationships in her life, like family and friends, who influenced her in different ways. But again, this is all just speculation without more details.
I don't have a definite answer for that. But usually, the story could take unexpected turns or build on existing character developments. Maybe it'll be revealed in future episodes or spin-offs.