Iruka could still be an important ally. Even though Naruto's situation is different, Iruka would probably be drawn to his positive attitude. And the Third Hokage would also be on his side. He was always looking out for Naruto in the original story, and that would likely continue. Plus, any of the ninja who were friends with Minato would probably be friendly towards Naruto as well.
The main antagonists could be the villagers who fear Naruto's mini Kyuubi form and try to drive him out of the village. Their prejudice and fear act as a major obstacle for Naruto, who just wants to be accepted.
The overall story arc would shift. In the original, the Kyuubi attack was a huge event that shaped Naruto's life and the village's future. If he was born before that, the village might not be as focused on security against the Kyuubi. Naruto's training might also be different. He might not have to struggle as much to gain recognition, so his training could be more traditional and less about proving himself. This could lead to different ninja skills and abilities compared to the original Naruto.
One implication could be that Naruto's life might have been more normal at first. Without the immediate post - Kyuubi attack chaos and the villagers' fear and hatred towards him from the start. His parents might have had more time to be with him, and he could have grown up with a more stable family environment, which would have likely affected his personality development in a positive way.
Well, one possible plot could be that Naruto's mini Kyuubi form is initially out of control. He might accidentally attack the village when he was a child. But then, through the help of Iruka and Kakashi, he starts to learn to control this power. They teach him chakra control techniques specifically designed for his unique situation.
Well, it could change a lot. For one, Naruto might grow up with his parents. This would mean he'd have a completely different upbringing. He could be trained by his father, Minato, from an early age, perhaps learning all kinds of advanced jutsu. His relationship with the village would also be different. Instead of being an outcast, he might be seen as a hero's son, and be respected right from the start.
His mother, Sally, would surely be one of his allies. She has always been there for him. Also, Grover could be his ally as they have a long - standing friendship. Grover might see Percy as an even greater protector of the nature spirits now that he's a god.
Potential allies? Well, Jiraiya for sure. Jiraiya was always interested in unique and powerful ninja. If Naruto was born earlier, Jiraiya would likely be drawn to him. And maybe some of the members of the Uzumaki clan who were still alive at that time. They could have guided Naruto in using his clan's unique abilities. Enemies? The Akatsuki could have emerged as enemies much earlier. Their goals were often in conflict with the stability of the ninja world, and Naruto, with his powerful potential, would be a target for them.
Definitely the Na'vi. They are the native inhabitants of Pandora and would likely see Naruto as an ally, especially if he shows respect for their land and culture. His skills could be useful to them in their fight against any common enemies.
Sasuke could be one of his main allies. Despite their past differences, they could put aside their issues to support Naruto in his role as the King of Monsters. Sasuke's powerful combat skills would be a great asset in battles against those who oppose Naruto.
Some of the lesser - known Ame ninjas who are tired of the constant conflict. They might see Naruto as a symbol of change and ally with him. These ninjas could have unique skills that Naruto can learn from, and together they can work towards a more positive future for Ame.