One common theme is the depth of Leia's love for Han. The fan fictions often show how this love doesn't die with Han, but rather transforms into a deep - seated grief. Another theme is the struggle to move forward. Leia has responsibilities, but her grief over Han makes it difficult for her to fully engage in her duties.
There's a fan fiction called 'The Empty Space Next to Leia'. In this story, it vividly portrays Leia's grief through her daily routines. Everywhere she looks, she is reminded of Han. The author does an excellent job of making the reader feel Leia's pain, from her silent tears at night to her moments of anger during council meetings, all because of Han's absence.
One possible storyline could be how they deal with the challenges of impending parenthood while still being involved in the galactic struggle. For example, they might have to find a safe place to raise their child away from the Empire's reach.
In time travel situations, they may have to rely on each other in ways they haven't before. For example, if they travel to a time when the Force is not well - understood, Luke may have to depend on Han's non - Force - related skills more. Leia might find herself in situations where she has to mediate between Han and Luke more often, strengthening their bond as a trio. Their relationships would grow deeper as they face new challenges together.
If they time travel, their relationships might become more complex. For example, if they go back in time to before they met, they might initially not trust each other as they do in their own time. Han might be more distrustful of Luke's Jedi abilities, and Leia might not see Han as the hero she knows him to be. But as they face challenges together in the past, they could form deeper bonds in different ways than they did originally.
They could time travel to a parallel universe where the roles are reversed. In this universe, Luke is a Sith, Leia is a bounty hunter, and Han is a political leader. They are shocked by these changes but soon realize that they need to find a way back to their own universe. Along the way, they learn about the different choices that led to these alternate identities. Luke sees how easy it was for him to turn to the dark side in this universe, which makes him more determined to stay on the path of the light in his own world.
The pregnancy might change the way other characters interact with them. Allies could be more protective, while enemies might see it as a new vulnerability to exploit. For example, the Empire could try to use the pregnancy as a way to blackmail or manipulate them. It also gives fanfiction writers a chance to explore different aspects of the characters' personalities as they adapt to this new situation.
One idea could be that they travel back to the time before the fall of the Republic. Han could try to use his smuggler skills to prevent certain events that led to the rise of the Empire. Luke might seek to train with the Jedi of that era, and Leia could try to influence galactic politics to avoid the chaos that ensued.
There could be characters from the Rebel Alliance. For example, Mon Mothma, who is a key figure in the political side of the rebellion. Her interactions with Leia would be important in the context of the novel as they both work towards the same goal of overthrowing the Empire.
Often, their interactions start from a place of conflict. Anakin's past actions as Vader create a barrier. However, as the story progresses, they may start to understand each other more. For example, Anakin could reveal his true self to Leia, the self that was once a good Jedi. This could lead to moments of deep connection and mutual respect between them. They might also have to work together against a common enemy, which would force them to communicate and cooperate, leading to a more developed relationship.