If Kushina trains Naruto for the Chunin Exams in fanfiction, it would be an amazing story. Kushina was a powerful kunoichi. She could train Naruto in areas he lacks, like better chakra control perhaps. Also, their mother - son bond would be beautifully explored during the training sessions. Naruto would probably become more confident and his combat skills would improve significantly.
One of the main challenges is time management. The Chunin Exams are approaching fast, and Naruto has a lot to learn. He has to quickly grasp complex ninja techniques that Kakashi is teaching. Another biggie is dealing with his own impatience. Naruto is eager to prove himself and might rush through the training, not fully absorbing the lessons.
Perhaps Asuma helps Naruto to better control his chakra in unique ways. He could introduce some special training methods that are not taught in the regular academy. This would give Naruto an edge in the exams, like being able to use more powerful jutsus without exhausting his chakra too quickly.
One of the main challenges could be the lack of immediate feedback. When training alone, Naruto doesn't have a partner to correct his mistakes right away. For example, if he's working on a new jutsu, he might not realize he's performing it slightly wrong until it fails completely. Also, he has to motivate himself without the competition or support of his peers. He might get bored or frustrated easily since there's no one around to cheer him on or push him further.
Asuma's training might make Naruto more disciplined. Naruto is known for his impulsive nature, but under Asuma's guidance, he could learn to think before acting.
In this fanfiction scenario, Naruto and Yugito could have some really interesting interactions during the Chunin Exams. Maybe they start off as rivals, each determined to prove themselves in the exams. Naruto with his unwavering determination and Yugito with her unique skills. They might end up in a match against each other, and through the battle, they gain a newfound respect for one another's abilities.
One idea could be that Naruto forms an unexpected alliance with Anko during the Chunin Exams. Maybe they team up to uncover a hidden plot within the exams that threatens the safety of all the genin. Anko, with her experience, could help Naruto see things from a different perspective and he, in turn, could inspire her with his determination.
One idea could be that female Naruto has unique jutsu in the Chunin Exams. For example, she might have a more refined version of the Shadow Clone Jutsu, which surprises the opponents and judges. Her character could also show more emotional intelligence during the exams, like using her understanding of others' feelings to her advantage in battle, perhaps by predicting their moves based on their emotions.