For Ahsoka, her character could be developed further by exploring her feelings of being an ex - Jedi. She could struggle with her place in the galaxy now that she's no longer part of the Jedi Order. Rex, on the other hand, could be developed by showing his life after the Clone Wars. Maybe he has a hard time adjusting to a new way of life without the structure of the military.
Lux could be developed by being put in situations where he has to make tough moral choices. Maybe he and Ahsoka come across a situation where they can save many lives but at a great cost. His decision - making process would show his growth as a character.
A third storyline could be set during a time of great chaos in the galaxy. Ahsoka and Rex find themselves in the middle of a power struggle. They have to use their skills and knowledge to try and bring some sort of peace. Ahsoka's Jedi training and Rex's military experience would be put to the test as they navigate through political intrigue and battles against different factions.
In the official Star Wars lore, there is no explicit romantic relationship between Ahsoka and Rex. Their relationship is mainly one of comrades and friends. They have a deep bond based on their shared experiences in the Clone Wars, fighting side by side and respecting each other's skills and loyalty.
One possible fanfiction could be about Rex and Ahsoka going on a secret mission together. They might face a new and dangerous enemy that the Republic has not yet encountered. Rex would use his military tactics and Ahsoka her Jedi skills to overcome the challenges.
One way is through shared secrets. For example, they could discover a hidden Jedi prophecy together and keep it a secret from the Jedi Council. This would create a special bond between them. Another way is by having them save each other's lives multiple times. Each time, their trust and respect for each other would grow.
One way to develop Ahsoka and Lux further is to explore their backstories more deeply. For Ahsoka, we could learn about her early days as a Padawan, and how those experiences shaped her. For Lux, we could find out more about his family and what led him to be so rebellious. This would give more context to their characters and make their interactions in the fanfiction more meaningful.
For Fives, his loyalty and his growing doubts about the Clone Army's role could be explored more. Maybe he starts to question the Jedi's leadership in a deeper way after his experiences. For Ahsoka, her growth outside of the Jedi Order can be further developed. She could learn new skills from different cultures.
One common theme is loyalty. Rex and Ahsoka have a deep loyalty to each other that dates back to the Clone Wars. In many fanfictions, this loyalty is tested but always prevails. For example, in stories where they are faced with difficult choices that could put the other in danger.
Yes, there are quite a few. You can check out platforms like Archive of Our Own. Some fanfictions focus on their adventures together and how their relationship might develop in a romantic way, with beautiful descriptions of their interactions.
Perhaps a fanfiction where Rex and Ahsoka have to infiltrate an enemy base. Ahsoka could use her Jedi mind - tricks to get past guards, while Rex would be in charge of the technical aspects like disabling security systems. It would be full of suspense as they try not to get caught.