yeah, but they still use it, hence cooking ingredient by technicality

some people add gold leafs to their food. you make it out of gold hence gold could be considered an ingredient. also someone here clearly never ate Rorona's Gold Pie https://i.postimg.cc/Fs5N7Ybf/i.jpg

not as bad as some other ending recently. but this feels like it could have used some 5-6 more chapters to round things out properly

well i guess that debunks some unfounded theories someone has a while ago

i disagree since i think most plot threads apart from main couple ended meh. and it's more about the resolution of the main problem, which was the arc before the ending arcs

kaguya ending was meh but it was more ass on other characters resolution and and how they resolved the main problem. this is just ass. i hear aka is making another manga, not gonna read that

he is probably fine, remember Ichikawa's early days being all edgy like that too(but not actually having a box cutter, just random intrusive thoughts) it's probably someone else in the class

courage? this is already some of the dumbest ways for this to end with the so called smart guy plan being so incredibly stupid and then he actually dies. this is actually fitting with his aka's endings so far Kaguya's happy end had to rely on the opposing party being incredibly incompetent and stupid for them to lose easily. this tragic end had to have the usually calculating Aqua do the stupidest thing possible for him to die like this

while Roars seem kind of good the rest are still very horrible to humans. which is exactly why they are basically forced to be the starters of this war to most likely get wiped out so the other bloodlines have an easier time

did you actually see what happened in the first few pages of this chapter? gender is very relevant. moreover the MC refers to him as brat and would probably be able to tell if female. also he existed way before MC's daughter was killed.
as for your points:1. can't think of a reason atm but the other points are weaker. 2. woman who lost her only child and joined a cult happy to feed what people assume is a kid, it's not a surprising outcome since she was and still is mentally unstable to do these things. 3. he is a cult leader most of them have their cult treat them like an object of worship or a king and are usually perverts. 4.basically impossible since gender doesn't match and IT IS important.
i think it's possibly more logical the cult leader is a replaceable youth and another one controls the cult then your theory. though a weirdo is still an option

nah this is very obviously referring to Super Mario 64 speedruns , those have been kind of popular again recently

he had a daughter...

??? how would that make sense i don't recall any mention of other kids he had with his wife.

and so will this series soon since it's ending

i don't think there are actually any spoilers to begin with, i think this series started last month so this is probably the most recent chapter

i remember the last arc, but apart from the how doing the same twist twice wouldn't be interesting this time it wouldn't be logical. since she already touched the detective before checking anita, she would probably know if the detective was a murderer so why do that in the first place? that being said i think she technically touched everyone before going to anita too so it either makes it less likely that anyone she touched before is the culprit, or she wants to check if they are connected or accomplices in some way since she might not be able to gather that info from touch. but the action of actually going to anita is definitely to help the detective and i feel there's 99.99% chance he is good

i doubt the 6th option since she seems to be doing this to help the detective, she wouldn't try to contact anita if she knew ahead of time the detective is bad. somewhat doubt the 3 "unique" people working since she said she thinks they are good people, but this is not as strong to make them innocent

she will probably be the winner, it seemed obvious she will be a love eater and i love that they revealed it so early but also looks like she is about to develop feeling for him too

while the old man might be wrong, do not get confused. he didn't see 4 confessions and said "must be 4 love eaters!" he knows/assumes 4 love eaters are within the new students and did a simple 1+1 to tell him that those 4 confessions are likely from love eaters. if he could tell from seeing the footage then he would know who the love eaters were and the entire premise of this manga would fall apart