Nya would be very happy for her brother Kai. She would likely be there for Skylar, sharing her own experiences if she has any relevant ones. Lloyd might see it as a new chapter for Ninjago. He could be thinking about how the baby might grow up to be a great hero or play an important role in the future of Ninjago. And the other ninja would come together as a family to support Kai and Skylar through this big change.
Well, they might be shocked at how much technology has advanced in the future depicted in the fanfiction. Maybe there are new types of elemental powers or different ways of training ninjas. It could also be that the relationships between characters have changed in unexpected ways, and they would have to come to terms with that.
Jay would probably be very vocal. He'd be shouting for help and freaking out a bit. Kai would be angry at whoever or whatever hurt Zane and be ready to fight back immediately. Lloyd, being the leader, would try to stay calm on the outside but be very worried inside and start coming up with a plan to help Zane.
His friends, like Kai, would be very protective. Kai might get angry and rush into battle to avenge Lloyd's injury. Jay would probably be more worried and try to use his technical skills to find a solution to heal Lloyd.
They might gain a new perspective on their own abilities. If the future fanfiction shows ninjas with enhanced powers, the past characters could start to think about how they could develop their skills further. For example, if in the future they can combine elemental powers in new ways, the past ninjas might start experimenting.
He would probably be quite amused by some of his past antics. For example, his constant pranks on Iruka-sensei. But at the same time, he'd also see the pain he carried from not having his parents and realize how that influenced his actions. He might react with a bit of regret for some of the stupid things he did out of loneliness, but also be glad that those experiences made him who he is today.
Ninjago might be interested in Ninjago fanfiction because it could offer new ideas for their own battles and challenges. The fanfiction world is full of creative minds, and there could be some brilliant strategies or concepts in those stories that they could adapt. Also, it could be a form of entertainment for them, just like how we enjoy fictional stories about other things.
If Ninjago watches Ninjago fanfiction, they could get a whole new perspective on their own world. Some fanfictions might show them in different relationships or situations that they hadn't considered before. It could also inspire them to do things differently in their own adventures. For example, if a fanfiction has a really clever solution to a problem they've faced, they might think about using a similar approach in their own world.
The other characters' reactions can vary. Pixal, if she's around, would use her technological knowledge to see if there are any internal damages to Jay, especially if it's related to his electrical components. The villagers of Ninjago might also show their support. They could bring food or offer shelter for Jay to recover. The reaction of the villains would depend on the situation. Some might see it as an opportunity to finish Jay off, while others might be impressed by his courage in getting hurt while fighting them.