[justsomeguy]

Watching episode 8 again after 9:

* KyoAni's floorplan is slightly different than the novel's, but most of the differences are concentrated in the front, far from the supposed crime scene.
* What a conundrum. Kounosu has what seems to be the best opportunity, but as the smallest girl she cannot be a serious match for Kaitou, who's the biggest and buffest guy. Heck, I don't think even two of the other party members will be enough to take him on silently and without injuries.
* There's no way all five other members were involved, because there would be no point for them to fake the discovery of the crime scene.
* Having the window be the focus of 2/3 theories, along with the apparent difficulty in opening it and getting in without Kaitou noticing, indicates it's probably not the entry point. The windows in the two rooms in the hallway are open though. (Both rooms appear visually identical, too, right down to the decay, the only difference being a spiderweb. If KyoAni is copy pasting rooms, then that would be a meta way of indicating they're not important?)
* There's still no purpose to the severed arm. There's nobody it could belong to other than Kaitou, and had to be inflicted after death. But there's not enough blood connecting it to the main pool under the body, which one would expect when an artery is severed. There's no splatter on any of the other characters either, and almost no way to clean up any that will occur (running water and cleaning supplies in a rundown building? No.).
* For that matter, what's the purpose of the murderer closing and locking the door anyway (and it's likely the murderer, because Kaitou has no reason to)? There's nobody else in that part of the theater to witness the crime anyway, and sealing the room would seem to leave more clues than just leaving it open.
* The door to the stage and the passageway behind the stage are both blocked. There's what appears to be a trapdoor between the two that's at odds with the floorplan. There's no other meaningful entryway besides the main door, but anybody who can fit through that will almost definitely attract Kaitou's attention and be too small to win a struggle.
* The murder has to occur in the short timespan during the party's separation, without uninvolved members noticing the perp's movements.
* The only enlightening things about episode 9's theories are: the unused rope; discrepancy in the amount of blood used; Hyongou was familiar with the building and did not intend for the window to be the entryway.
* The mystery is supposedly solvable even in the film's unfinished state, which would mean that the things that are not shown are not important, meaning no undocumented entryways and not the unused rope.