It's during moments like this when Padmé Skywalker looks at her children, and instinctively knows what their lives would be if all had gone according to plan.
If all had gone according to plan, and Leia had not offered to take Bail's place aboard the corvette when Breha fell ill, she would be safely on Yavin, just coming in from her rounds scouting the perimeter, teasing her brother as she couldn't help but do. But Leia has too much of her father in her, and Padmé can only hope she didn't whip out her lightsaber for all to see the moment she was boarded. Padmé is not entirely certain what Anakin has planned in terms of a rescue, but the cockpit of the stolen Imperial starship she's currently sitting in is as good a start as any.
If all had gone according to plan, and Luke's voyage to Ilum when he was eleven had not been intercepted, Palpatine would have no knowledge of his existence. He would not be obsessed with finding her son and manipulating him as he almost did Anakin, the man he's believed to be dead all this time. Luke would have spent the last seven years with the same freedoms afforded to Leia, who takes the name Janren when off-world, gallivanting across the galaxy with the liberty that only comes with anonymity. Padmé knows that Luke harbors no small amount of resentment towards Anakin and herself for holding him back, and she cannot blame him. It's not the nature of a Skywalker (or a Naberrie, for that matter) to be left behind.
If all had gone according to plan, and Anakin and she had announced their marriage at the end of the Clone Wars (the end that never came), Luke and Leia would not have grown up with a Jedi and a politician for parents. Anakin would have been expelled, and no doubt she would have been shooed out of office by Queen Apailana, who had views about such things. The twins would have grown up in Theed, moving to Varykino in the summertime with the rest of the family. Leia would have idolized Ryoo and Pooja until she was old enough to team up with them against her poor brother. Luke would have spent his afternoons in Anakin's garage, glowing as the most recent Nubian model came in.
If all had gone according to plan, and the war continued, yet the democracy she had devoted her life to had not failed, the Jedi Council would have taken her children from her. Perhaps they would have known who their father was, perhaps not. Anakin and she would have argued, of course, but Padmé would not have denied them the chance to fulfill their potential. Luke, who has a kind word for anyone when not sparring with his father, would have been better suited to the life of a Jedi than Leia, who has no filter for her emotions and takes orders from no one. They would not know that they were related.
But if all had gone according to plan, and she and Anakin had listened to the rules, their mentors, each other, their own reason, the twins would never have been born, and Padmé does not even let that option enter her thoughts, especially as her husband tosses her a stormtrooper helmet and a small moon appears in the distance.