Allen in these fanfictions is typically a complex character. He has his own goals related to the Millennium Earl and the Akuma, but his feelings for Lenalee add another layer to his personality. He might be hesitant in expressing his emotions at times. Lenalee, on the other hand, is very empathetic. She is able to sense Allen's pain and tries to ease it. Their relationship in the fanfiction is usually based on mutual understanding and a growing, unspoken love that gives both of them something to fight for.
Well, it's difficult to determine. Maybe it's based on real events but with some exaggerations or modifications. Or it could be completely made up. We need more details to know for sure.
Yes, there are. Some of the Kyle Katarn novels are highly regarded for their engaging plots and rich storytelling. They expand on his story and add more depth to the Star Wars lore.