Trust would be a major challenge. The team has seen her as an enemy for so long. Also, she'd have to adjust to their way of doing things which is very different from how she was trained in the Fire Nation.
One of the main challenges for Azula joining Team Avatar in fanfiction is her own pride. She's used to being in control and being at the top. In the team, she'd have to be more of an equal. Also, she might struggle with the idea of working towards goals that are not about Fire Nation domination. Her firebending skills, while useful, might also be a source of tension as the team might be wary of her power. She would need to prove that she has truly changed and wants to be part of their group for positive reasons.
Azula would face challenges like adapting to the team's values. Team Avatar values things like friendship and equality, which are not really emphasized in the Fire Nation. And she'd have to deal with the fact that she has hurt some of the team members in the past, so getting them to accept her would be tough.
He would face a huge ideological challenge. Madara has very extreme views about power and the ninja world order, which are completely different from Naruto's beliefs in friendship and cooperation. Naruto would constantly have to struggle not to be swayed by Madara's ideas.
She could bring a whole new dynamic. Her powerful firebending skills would be a great asset. But also, her complex personality might cause some internal conflicts within the team as they'd have to learn to trust her, given her past actions.
One challenge could be adjusting to the different technology and ways of the past. For example, if they go back to a time before modern ninja tools, they'd have to rely on more basic equipment. Another challenge would be not accidentally changing the future in a bad way. They might also face challenges like being suspected as spies since they are from the future.
One challenge could be adapting to the team's dynamics. Team 8 has its own way of operating, and Naruto is used to his own style with his friends. For instance, they might be more methodical in their planning, while Naruto is more of a 'jump - in - and - figure - it - out' type. So, he'd have to learn to follow their lead sometimes.
There would also be logistical problems. Finding proper medical care during the war could be difficult. And she'd have to manage her pregnancy while still being involved in the fight against the dark forces. She might not be able to participate in as many dangerous missions as before, which could make her feel guilty.
Naruto would face quite a few challenges. For one, his growth might be stunted as the team overprotects him. He could also face ridicule from outside the team who might see him as a weakling now. Moreover, he has to deal with the internal team dynamics where Sasuke may not be fully accepting of his new role and Naruto would have to prove himself constantly.
She would face the challenge of hiding her true gender. In a world full of knights and men in power, being a girl might not be well - received, especially if she wants to be involved in matters of magic and the kingdom. She also might have to deal with different expectations in terms of behavior and appearance compared to male characters.
If Naruto joins Team Avatar in fanfiction, it could lead to some really interesting dynamics. Naruto's boisterous and determined personality would contrast with the existing members of Team Avatar. He might teach them some of his ninja techniques, like the Shadow Clone Jutsu. And he could also learn a great deal from the bending abilities of Team Avatar members. Maybe he'd be especially intrigued by Aang's airbending, as it has some similarities to his own agility in combat.
One idea could be a story where the two teams compete in a friendly but intense tournament. They might face challenges that test their bending skills in new ways.
The plot could revolve around Ash's initial confusion and conflict. He might join Team Rocket thinking he can change them, but soon realizes it's not that easy. His loyalty to his old friends would be tested as he gets drawn deeper into Team Rocket's plans.