I'm not a theory person myself, but I have noticed a few things that I haven't seen adressed on any theory so far, I guess because they are all "recent" (from the last two years). If you know any theory that includes this, please tell me.
I was thinking "What was the point of Gosho showing us Asaka's photo in the webpage?". He could've pulled a Hagiwara and not drawn them. So I think the purpose of Asaka's photo in which you can't see anything but the hand is precisely that you can see the hand. Looking at that hand, I find it way too similar to the photo of "Kohji's" hand, the one with the scissors marks and the weird mark in the centre. That photo shows a suit, similar to the one Asaka was wearing. On the other hand, all Kuroda, Rumi, Mary, Yumi and Amuro have "visualized" Haneda collapsed with a dark clothing that doesn't reach anywhere near his hand. A hand that, btw, has the scissor marks but not the mark in the palm.
So, some things that could have happened are:
The one who died was really Asaka, not Kohji, and police colabored to hide this fact, as the image Amuro had in his PSB training is also the "suit hand". This could also mean the uploader has access to police files. In this case Kohji would be alive, presumably under police protection or something similar. He could be Kuroda for all we know.
The one who died was Haneda, who was wearing Asaka's suit or a similar one, and the images everyone think up are a fake that never happened. This would mean no one of the people underlined above were actually at the crime scene and are just reconstructing the crime which the info they know, that being how Kohji looked like in his shogi clothes, that he grabbed scissors and he had injuries. (I find this one a bit unlikely due to Rumi's flashbacks in the Edible Plants case)
The one who died was Haneda, who had changed into Asaka's suit or a similar one, and the images everyone think up have happened and form part of a police report or news or something Conan hasn't seen yet. In that case, the timeline of the case would be: Haneda wearing shogi clothes gets the scissors, gets beaten up and collapses on the floor with blood coming out of his mouth. That's the picture everyone thinks. He isn't dead yet though; he changes into a suit, gets somehow the mark in the center of the palm and finally dies. This is what the police find hence the photo in Amuro's training.