Another possible new ability is the power to control elements other than just alchemy's basic elements. For example, he could gain the ability to control electricity directly. This would make his attacks more diverse and powerful. He could send bolts of lightning towards his foes or use electricity to power up his alchemy in a new and unexpected way.
In some fanfictions, Edward Elric might gain the ability to manipulate time. This could be a really cool addition as it would allow him to go back and correct mistakes he made in his past, like the failed human transmutation that cost him his arm and leg.
He could gain the power of telepathy. This would enable him to communicate with others without speaking, which would be very useful in both combat situations and in his everyday interactions. He could sense the thoughts and intentions of his enemies, giving him an edge in battle.
In this fanfiction, he could gain the power of energy absorption. This means he could absorb any type of energy, be it magical, alchemical, or even kinetic energy from attacks against him and then use it to his advantage. For example, if an enemy attacked him with a fire - based spell, he could absorb the energy and then release it back as a more powerful attack. Or he could gain the power of astral projection, allowing his spirit to leave his body and explore places or gather information that would be otherwise inaccessible.
If he gains new powers, it might make some of his friends a bit wary at first. They could be afraid of how much he's changed. But his close friends like Alphonse would probably try to understand. His enemies, on the other hand, would see him as an even greater threat. Some might try to form alliances against him. Overall, it would shake up his relationships as people adjust to the new Edward with these powers.
If Edward gains the power to heal with a touch, it could bring him closer to those he has wronged in the past. He could use this ability to help those who were affected by his previous alchemical mistakes. This would lead to forgiveness and a rebuilding of relationships that were once strained.
Edward might meet his parents. Since he has the chance to go back in time, he could meet them when they were alive and perhaps learn more about alchemy from them, which could change his future actions.
They could start by comparing their different worlds. Edward would explain about the principles of alchemy like equivalent exchange, while Urahara would talk about the Soul Society and the way spiritual power works. This exchange of knowledge could be the foundation for their relationship in the fanfiction.
Perhaps it's a story where Naruto has the same kind of tragic backstory as Edward. Maybe Naruto loses Sasuke in a way similar to how Edward lost his mother and brother's body. So Naruto starts to study alchemy in the hope of getting Sasuke back. Along the way, he meets Edward and they learn from each other's experiences and fighting styles, and together they face the challenges in both their worlds.
Well, perhaps Edward could use his alchemy skills in the magical world of Hogwarts. He might be sorted into Gryffindor for his courage. He could start to learn magic along with the Hogwarts curriculum and have some interesting interactions with the students like Harry, Hermione and Ron. Maybe he'd show them some unique alchemy tricks and in turn learn some new spells.
Well, Edward Elric in Hogwarts would be quite a sight. He'd probably be super confused at first. I mean, going from his world of alchemy to a world of magic. He might try to use alchemy where magic is required and get some really strange looks. But he's a smart guy, so he'd quickly start to learn about magic. Maybe he'd even find a way to combine alchemy and magic in some unique way.
Well, it could mean Naruto would adopt Edward's sense of fashion. He might start wearing long red coats and black pants, just like Edward. In the fanfiction, Naruto could also learn about Edward's moral code. Edward has a strong sense of right and wrong when it comes to alchemy, and Naruto could use that to re - evaluate his own actions as a ninja. Maybe he would be more cautious about using certain jutsus that have a high cost or moral implications.
One possible outcome is that Naruto would gain a different perspective on alchemy. Edward's scientific approach to combat and his understanding of equivalent exchange could influence Naruto's way of thinking. Naruto might start to analyze his jutsu in a more methodical way, similar to how Edward approaches alchemy. For example, he could consider the energy input and output of his shadow clone jutsu more carefully.