Jeff the Killer is purely fictional. It's a made-up tale that has gained popularity in certain online communities, but there's no truth to it. It's all for scaring and thrilling those who enjoy such horror concepts.
I don't have that information. You might want to look on comic-related forums or social media groups to see if there's any buzz about Jeff Woods the comic's status.
Definitely real. Jeff Dahmer's horrific acts and his story have been extensively covered in the news and various true crime accounts. There's a lot of evidence and testimony to confirm it.