It might be Konohamaru. He looks up to Naruto a lot and Christmas would be a great chance for him to be part of a big celebration just like Naruto. He'd be eager to help with the decorations, try all the Christmas treats and play all the party games.
Naruto, of course. He loves any kind of celebration and the idea of Christmas with all its food, presents and fun would make him super excited. He'd be running around the village, inviting everyone and getting all the preparations done with great energy.
I think it could be Lee. He's always full of energy and enthusiasm. Christmas is a time of celebration and he would see it as an opportunity to show his positive spirit even more. He might be doing all kinds of acrobatics and showing off his skills to add to the festive mood.
Probably Goku. He has always been eager to know more about his Saiyan roots and having his two most important women in his life, Chi - Chi and Gine, meet would be a huge deal for him. He would be excited to see them interact and get along.
Probably Naruto. Since Minato is his father, he has always longed to know more about him. Meeting Minato and his team would be a dream come true for Naruto. He would be eager to hear stories from his father's past, about his training, and how he became such a great ninja. Naruto might also want to show off his own skills to his father and the rest of Team Minato.
Luffy, of course. He and Sabo have a deep history. They grew up together and Sabo was like a brother to him. Their reunion would be filled with joy, hugs, and probably a lot of tears. Luffy would be over the moon to have Sabo back in his life and on his ship.
Maybe Neville. He had a bit of a rough start at Hogwarts in primary school, but he grew so much. Attending the reunion would be a chance for him to show how much he's changed and to catch up with those who were there when he was finding his footing. He could share his experiences of becoming a confident and skilled wizard. Also, he might be excited to see the teachers who supported him along the way.
I think Shikamaru would be great for a Naruto party in fanfiction. He's smart and could come up with some interesting party games. Sakura would also be a good invitee. She could use her medical skills to make sure everyone is okay if there are any minor injuries during the party activities. And Rock Lee, his energetic and enthusiastic personality would really liven up the party.
Well, in this kind of fanfiction, the Christmas Party could be a time for reconciliations. Characters who had past differences, like Naruto and some of the villagers who once shunned him, could come together and celebrate. There might be a big snowball fight in the village, with all the ninja using their skills in a friendly way. The party could also include a special performance by Naruto, where he shows off his new jutsu in a Christmas - themed way, making everyone cheer and laugh.
I think Uraraka would be very excited. She has always been a big supporter of Deku. Meeting Future Deku would give her a chance to see how far he has come, and she might also get some inspiration for her own hero journey. Plus, she's a friendly and emotional character, so she'd likely be thrilled at the opportunity.
I think Thor could be really excited too. Thor loves a good warrior and Peter, with his spider - like abilities, would be an interesting addition to his view of heroes. Thor might be amused by Peter's small - scale heroics compared to his own grand battles and would enjoy seeing Peter's potential grow.
Probably Natsu. Since he has been searching for Igneel for so long, finding his family or getting some real family - related news would make him extremely excited. He's always been a bit of a lonely dragon slayer without his real family around, so a reunion would be a huge deal for him.
Natsu would probably be the most entertaining. His fiery and impulsive nature would lead to all sorts of comical situations at the beach. He might try to swim in lava - like hot water or accidentally burn someone's beach towel while trying to dry himself off.