Definitely Hermione. She is smart and would be able to help Ichigo understand the complex magic world. Also, Hagrid. He is kind - hearted and has a lot of knowledge about magical creatures, which could be useful for Ichigo.
Well, he would likely have a very different set of powers. Naruto is known for his ninja skills and chakra, while Ichigo has Soul Reaper powers. Naruto might struggle at first to adapt to the new spiritual world Ichigo lives in. He'd probably bring his tenacity and never - give - up attitude, which could lead to him quickly mastering some of Ichigo's basic abilities.
Naruto's exuberant and friendly personality would make Ichigo more approachable. Usually, Ichigo can be a bit moody and standoffish, but with Naruto's influence, he might be more open to making new friends and allies. This could lead to different interactions within the Bleach universe.
One possible plot is that Ichigo is reborn as Harry Potter's long - lost twin. He would then have to deal with the same kind of prophecy and the threat of Voldemort. But being Ichigo, he would approach things in his own way. He might not rely so much on magic wands but use his own spiritual power which could be disguised as a new form of magic in Hogwarts. This would cause a stir among the professors and students alike.
One interesting plot point could be how Ichigo, with his unique powers from the Bleach universe, adapts to the world of Naruto. Maybe he uses his Zanpakuto skills in new and unexpected ways within the Naruto setting.
The character development might start with Ichigo having to relearn things in his new identity as Naruto. He has to adapt to the ninja way while still holding onto some of his old values from being Ichigo. This creates an interesting dynamic as he grows in this new world.