Well, in such a fanfic, Naruto would likely be considered the strongest. Since it's a 'Naruto strongest' concept in a Fairy Tail setting, Naruto brings his powerful ninja skills like the Rasengan and Shadow Clone Jutsu. His ability to quickly adapt and his large chakra reserve would give him an edge over many Fairy Tail characters.
I'm not a fan of web novels. I'm just a fan of web novels. I can't provide any information about Naruto. If you have any other questions, I will try my best to answer them.
The most powerful person in the group was Li Heng, the hero of the mythical realm. I recommend a novel called "One Man's Nightwatchman". It was a light novel, a derivative Doujinshi novel. It revolved around the story of the main character, Ye Yan's Nightwatchman. At the same time, it also involved some of the characters and plots under One Man. The reason for the recommendation is that if you are a fan of only one person, then this novel is definitely not to be missed~I hope you will like this fairy's recommendation.
In a crossover, it really depends on how the powers are combined. If Naruto could somehow combine the Nine - Tails' chakra with Sage Mode and then learn some ki techniques from the Dragonball Z side, he could be extremely powerful. But Goku has been training for a long time and has access to godly ki. So he would be a top contender as well. Vegeta too, with his own determination and power - ups, could also be in the running for the strongest.
It's hard to say. Goku in his Super Saiyan forms has incredible power and can destroy planets. But Naruto has the Nine - Tails' power and Sage Mode. If we consider Naruto at his peak with all the tailed beasts' power combined, he could give Goku a tough fight. However, Goku's ability to constantly increase his power level might give him an edge in the long run.
However, it might also depend on the situation and how their powers interact. If they were to fight in Naruto's world, Naruto might have an advantage as he knows the terrain better and has his ninja allies. But in Danny's world, Danny would be more at home and could use the unique features of the Ghost Zone to his advantage.
It's hard to say for sure. Goku has the ability to reach extremely high power levels and transform into powerful forms like Super Saiyan God. However, Naruto also has the power of the Nine - Tails and his own Sage Mode, which makes him incredibly strong. If they were to fight, it would depend on the circumstances, like the location and if Naruto could use his ninja tricks to his advantage.
It's hard to say for sure. Naruto in his Sage of Six Paths mode is extremely powerful, with access to a vast amount of chakra and the ability to create and manipulate Truth - Seeking Balls. But Ichigo, when he reaches his final form, can also be a force to be reckoned with, having the combined powers of his Hollow, Quincy, Soul Reaper, and Fullbringer heritage.
One could argue that Superman is among the strongest. He has superhuman strength, can fly, has heat vision, and is nearly invulnerable. He has saved the world countless times in the DC comics universe and has faced off against some of the most powerful villains.
In the realm of Japanese manga and anime, Saitama from 'One Punch Man' is a very strong character. As his name implies, he can defeat any opponent with just one punch. He has trained so hard that he has broken through all his physical limits, and no enemy has been able to pose a real challenge to him so far. His strength is a kind of comical extreme in the world of anime characters.