Okay so if I'm reading the rules right, the scientist gets to pick the order they use the cards in? I would assume if that is the case the scientist would pick the biggest most useful clues first.
I'm also agreeing with Bylthe and Vera that it is probably more helpful to look at what clearly would be a better pick of something else than to look at what fits the clue because, well, pretty much anything can fit any clue if you are creative.
So with that being said..
Cause of Death- Suffocation, Severe Injury, Loss of Blood, Illness/Disease, Poisoning, Accident
So, it's NOT - Suffocation, Loss of Blood, Illness/Disease, Poisoning, or Accident.
I think there is a lot of potential crossover with Loss of Blood and Accident, but Suffocation, Illness/Disease and Poisoning are clearly different.
Location of Crime - Playground, Classroom, Dormitory, Cafeteria, Elevator, Toilet
So it's NOT - Playground, Classroom, Dormitory, Elevator, Toilet.
Okay, Playground, Classroom, Dormitory and Cafeteria all have elements of a school so there's some crossover there, but Elevator and Toilet are clearly different, and also Cafeteria has the food prep thing going on which may make something stand out more.
So here are my thoughts. I am NOT comparing this to anyone else's as I write. I think it's better to do it this way and then go back and see what others think.
Red = I think it matches very well
Orange = I think it could match but could also match something similar (i.e. Blood Loss/Severe Injury)
Green = It could fit but I think there's a better choice, or there aren't any great choices for this clue among the options
Blue = Very sure it's not this, a clearly better choice
Means of Murder Cards: Powder Drug (Poisoning/Accident), Metal Wire (seems like Suffocation would be the best choice...but not as strong on this one), Pillow (Suffocation), Sculpture (I think this fits pretty well)
Key Evidence Cards: Pocket Watch (Not Blue because I don't think it fits any all that well, but for that reason I'm not putting it any higher), Surveillance Camera (I think elevator would be a better choice for this but again none are great), Exam Paper (definitely classroom), Hourglass (again, none are great for this, but I would have picked classroom I think)
Overall: Yugi is looking pretty good. One good match for means of murder, but no evidence that I think fits. Threat Level: Blue.
Means of Murder Cards: Poisonous Gas (Suffocation, Poisoning obvious better choices), Scarf (Suffocation/Accident clearly better choices), Electric Current (Accident is equally good here, but Severe Injury also fits), Plastic Bag (Suffocation obviously better)
Key Evidence Cards: Test Tube (Classroom obviously better), Iron (I'm assuming this is a clothes iron, in which case I would have gone with dormitory), Maze (I think this would go in classroom or playground depending on how big it is), Cassette Tape (Elevator Music? Maybe Dorm or Classroom? Don't see how this possibly gets Cafeteria)
Overall: Strangefate is looking pretty safe too, unless I'm misunderstanding something really obvious I don't think it's him. Threat Level: Blue
Means of Murder Cards: Sniper (I think Severe Injury is the best for this), Illegal Drug (Poisoning/Accident both better), Drill (Equal to Loss of Blood, but both are good), Liquid Drug (Illness/Disease, Poisoning, Accident all better)
Key Evidence Cards: Seasoning (Perfect fit), Skull (probably Classroom? None are a great fit), Push Pin (Classroom, Dormitory, both better, nothing great though), Soft Drink (Best fit)
Overall: There are multiple ways Remiel is guilty here. Also, is Remiel. Threat Level: Red
Means of Murder Cards: Mercury (Poisoning, Accident both better), Drown (Suffocation obviously), Chainsaw (Loss of Blood and Severe Injury both fit this equally well), Boxcutter (Same)
Key Evidence Cards: Jacket (Honestly could go in pretty much any except Elevator/Toilet), Snacks (Cafeteria is a good fit, but so is Classroom, Dormitory, etc), Dice (None are great fits), Spring (would think Classroom/Playground before Cafeteria)
Overall: Can't rule him out quite yet, but case isn't that great. Threat Level: Orange
Means of Murder Cards: Alcohol (Illness/Disease, Poisoning, Accident all better), Kerosene (Severe injury would be the best fit if you take this to mean set on fire, but Poisoning/Accident could work too), Machete (similar to Chainsaw/Boxcutter), Hammer (Blunt Force Trauma, best described by Severe Injury than the other options)
Key Evidence Cards: ID Card (You could find this in Dorm too, but both work well), Certificate (This is kind of vague, but like, a food rating certificate or health inspection one fits only here, of course like a report card fits better in classroom, compliance certificates hang in elevators...hmm), Internet Cable (Classroom/Dorm better choices), Table Lamp (Dorm is only good choice for this, never been in a cafeteria with a table lamp)
Overall: Some good matches, but missing a match of 'best choice' options. Still pretty suspect though. Threat Level: Orange
Means of Murder Cards: Wire (an electric wire would seem to be more Accident related, a strangling wire more Suffocation related, either way seems weak), Razor Blade (same as other bladed things, severe injury/blood loss both good fits), Whip (pretty much same), Bamboo Tip (and same)
Key Evidence Cards: Coffee (It's a good fit, but hardly the only place you see coffee), Menu (best fit), Playing Cards (Dorm probably equally good, but this fits well too), Tie (would probably pick Classroom or Elevator first)
Overall: Some strong evidence here, but not quite a smoking bullet on the means of murder. Threat Level: Orange
Means of Murder Cards: Wrench (best choice), Surgery (I think probably Accident/Loss of Blood fit pretty well too), Bite and Tear (Loss of Blood equally good), Wine (Illness/Disease, Poisoning, Accident all better)
Key Evidence Cards: Badge (Honestly don't think any match this), Comics (Same), Video Camera, (mayybe but I would have picked elevator first), Leather Shoe
Overall: Lots of strong means of murder cards, no strong evidence cards. But I might be missing something as many of them seem vague to me. Threat Level: Green
Means of Murder Cards: Trophy (bludgeoning death, best fit), Push (I think being pushed off a big cliff or into traffic, this is the best pick), Folding Chair (another beating death?), Radiation (Poisoning, Illness/Disease, Accident all much better choices)
Key Evidence Cards: Numbers (Classroom/Playground/Dorm/Elevator all much better choices), Dictionary (Classroom is obvious choice), Banknote (of the choices available, a Cafeteria is the only place you'd use money), Switch (not a great fit for any but cafeteria is a real stretch)
Overall: Some definite possibilities here. Threat Level: Orange
Means of Murder Cards: Blender (could also be loss of blood/accident, but if you bludgeon someone with it this fits best), Towel (Suffocation, Accident better choices), Venemous Snake (Poisoning), Chemicals (it could lead to severe injury but I think illness/disease or poisoning fit better)
Key Evidence Cards: Note (Classroom much better), Bullet (not a great fit for anything), Timber (again not a great fit for anything), Cat (and again not a great fit for anything)
Overall: I think pretty in the clear, although some vague possibilities remain. Threat Level: Green
Means of Murder Cards: Poisonous Needle (if the FS picks anything but poison while its in the name than the FS is the killer!!), Machine (Severe Injury/Accident both fit pretty well), Cleaver (equal to blood loss as all over blades), Unarmed (Fits best of available options)
Key Evidence Cards: Lens (I'm thinking classroom maybe? Not great for any), Mirror (Toilet obvious choice), Steamed Buns (best choice), Dentures (I think Cafeteria is best choice, since these involve eating)
Overall: Some possibilities. Not really ready to commit here though. Threat Level: Orange.
Means of Murder Cards: Ice Skates (all other bladed instruments), Locked Room (would think Suffocation/Accident before Severe Injury), Sulfuric Acid (Best fit), Arsenic (Poisoning)
Key Evidence Cards: Safety Pin (no great matches, not sure what I would pick for this tbh), Wig (same, but maybe Toilet is closest), Confidential Letter (think like passing a note I would go classroom), Map (Classroom)
Okay not really gonna pretend I can be objective about myself but attempting to be I guess. Why not? Trying to compare these to others I'd go with Green.
Also does anyone else think this combination of items makes me seem like Tonya Harding? Ice skates, Wigs, Confidential Letters, Locked Rooms...no? Just me? Ok then...
Hmm okay those are my raw thoughts.