Well, one possibility is that Aang's friends could find a way to heal him. Maybe Katara would use her waterbending skills in a new and innovative way to reverse the damage caused by the lightning. Another idea is that Aang could enter a spiritual realm while in this injured state and gain new insights or powers that would help him when he recovers.
The impact on the plot could also be emotional. Aang being shot by lightning would be a huge shock to his friends. This could lead to moments of self - doubt among them. For instance, Katara might blame herself for not being able to protect Aang. Sokka might question their ability to continue their journey without a fully functional Avatar. These emotional upheavals could add depth to the characters and drive the plot in new directions as they struggle to overcome their internal and external challenges.
Yes, if the title 'aang is a firebender fanfic' is to be taken literally, then aang is likely a firebender within this fanfic. However, without actually reading the fanfic, there could be some sort of plot twist or alternative interpretation that might make it not so straightforward.
Since 'lemon' fanfic is inappropriate, we can't really discuss the characteristics in that context. But in general, aang is known for his kind - hearted and adventurous spirit. Toph is strong - willed and independent. In proper fanfic, these traits are often explored in their relationship, like how aang's optimism might contrast with toph's more cynical view at times.
He could meet his future self. It would be an interesting encounter as he could learn from his future experiences and wisdom. Or he might meet people who have studied his past adventures and see himself through their eyes.
Possibly they are random villagers who were caught in the crossfire of a conflict between different bending factions. Aang, being the Avatar and a symbol of peace, feels responsible for burying them and ensuring their spirits are at peace.
He might start by observing. Aang is a curious person, so he'd likely watch how people live, how they interact with technology. He may also try to find other benders to learn about any new developments in bending. And he'd probably use his kind heart to make friends easily in this new future environment.
Sokka could be one of the main characters. He might be the one helping Aang with his schoolwork, especially in subjects like history or math, using his own knowledge and quick thinking.
Aang might go into a deep state of depression. He has always been an emotional character, and having his heart broken by Katara, someone he loves deeply, could send him into a downward spiral. He might isolate himself from his friends and stop practicing his bending for a while.