Hm.....I think ryan....killed them....for viscoui he may of got the burn from the start button, ryan may of broken the start button (toolbox used) and viscoui fell back giving a chance to the killer to swing and hit viscoui with the axe. as for royal i think that royal saw ryan doing something weird so he pretended to show him something and then behind him and chocked him. (in the pc room.) since ryan didnt have time to close the computer he tried his best to get royal's body to the hanging point before the others found the body, and for the scarf part he ripped it off by accident while trying to tie the body up. Other killer could be gavin or nils but i think ryan the most.
Ok. so, i think kana was in the in the place getting something for her cheerleading when the killer threw the cleaver at her leg so he fell down and then stabbed her, she struggled and tried to grab bat but the killer grabbed it off her and hut her. the hammer flew off the shelf and fell onto the floor and doing..nothing. the killer took 2 knifes so it distract the others and confuse them on what was the murder weapon. as the bat benning there...i don't know. im guessing its gelatin..idk.