It's hard to say. Harry has a natural talent and courage, which could help him succeed. But Draco is well - versed in the pure - blood magic traditions and might have an edge in some aspects. Snape might be tougher on Harry due to their past, but that could also make Harry more determined. So it could really go either way depending on how the story is written.
It could be Harry. Since he is the main character in the original series, many fanfictions might still revolve around him. He has a complex relationship with both Draco and Severus, so it's easy to build a story with him as the central figure.
Well, it could be that in the 'Harry and Draco apprentice with Snape' fanfiction, they end up learning a lot about the Dark Arts from Snape, not in an evil way but in a way to defend against them. Harry would be skeptical at first but then realize the importance. Draco might be more eager as he has some knowledge of the Dark Arts from his family. Snape could also teach them how to brew complex potions that are useful in both dueling and healing. There could be some rivalry between Harry and Draco in terms of who can master the skills faster, but also moments of cooperation when they face difficult tasks.
In 'harry is an apprentice fanfiction', apart from Harry, there might be other apprentices too. They could be his friends or rivals during his apprenticeship. Also, we can't rule out the appearance of some of the main antagonists from the original series, as they might try to interfere with Harry's apprenticeship journey.
Hermione Granger would be a strong contender. She's highly intelligent and would quickly learn all the rules and strategies of WWE Wrestling. She could use her magic to study her opponents' weaknesses before a match. And if she needed to, she could use spells to immobilize her opponents for a short time, like the Petrificus Totalus spell, and then make a quick pin.
Rock Lee could succeed as well. His dedication to taijutsu and his physical strength are his assets. He can move extremely fast and his attacks can be very powerful. In a solo team situation, he could focus all his energy on getting the bells without any distractions.
Snape's teaching style would have a profound impact on Harry. Given that Snape is a master of his craft, he would not tolerate any sloppiness from Harry. Harry would have to be more meticulous and detail - oriented. This would be a change from his usual somewhat haphazard approach. Snape might also use his own experiences to teach Harry about the importance of self - control. Since Snape has dealt with his own inner demons, he could guide Harry in managing his temper and using his emotions to fuel his magic in a more positive way. Also, Snape's knowledge of the darker aspects of magic would give Harry a more comprehensive understanding of the magical world, which could be crucial in his future battles against dark forces.
Snape might also keep what he saw to himself at first. Instead of immediately confronting them, he could choose to observe them further. He might be curious about what they were really up to and use his skills as a spy to find out more. This way, he could gather more information before deciding on the best course of action, whether it be punishment or something else entirely.
Hermione would be a very likely ally. She's smart and resourceful, and could help Harry figure out the best ways to use magic against the Chitauri. Ron might also be there, with his loyalty and fighting skills. Additionally, some of the more experienced wizards or witches from Hogwarts could potentially join in to help Harry.
Another possible main character could be a new villain. Since Harry is in a new role as an apprentice, there could be someone who wants to steal the secrets of Ollivander's wand - making. This villain could be a dark wizard or a rogue wizard who has his own motives for wanting to control the wand - making process. Harry would then have to protect Ollivander and the shop from this threat.
Harry Potter is a very likely character. Given his often - tense relationship with Snape, detention with Snape could be a great opportunity to explore their dynamic further. Harry might learn more about Snape's motives during these detentions, or they could have some unexpected conversations that change Harry's perception of Snape.