Inari-zushi. Basically rice that is stuffed into a packet of tofu skin and then fried. Since olden times, the people would use them as offerings to the Kami of harvest, Inari-no-Kami, to thank her for bountiful harvest hence the name. Because the messenger of Inari-no-Kami are two foxes, popular culture assumes the Kami herself is also a fox, explaining why almost every fox girl in media nowadays has a craze for inari-zushi.

Ah yes, the totally-not-Tokino-Sora aka Soda-chan aka Sofa-chan aka Aka-chan.

He was doing part-time after school though? At the start the girls just finished their afterschool announcement, one even said "stay safe on your way home" meaning school is already over.

Girl being nekkid and slutty: i sleep
Accidental pantyshot like that last page: real shit
Combined with her flustered expression: I ASCEND

One time while going to the mall with family, I literally could not stop sneezing while walking through the perfume aisle. I don't think I have like an allergic or anything because my family uses perfume quite frequently, but the perfume aisle definitely stocked something a fierce that day.

"Not incorrect" =/= "the right choice". Sometimes there isn't even a "right" choice. Still doesn't meant the first choice, one with dubious rate of success at best at that, is immediately the "best" one. It's something to consider if they're really scraping the bottom of the barrel in term of what solutions they have left for the task at hand, which currently they're barely scraping the surface and is why we even have the whole investigating the secret archive in the first place.
And again, you kept emphasizing on his "immaturity" or "lack of preparedness" or whatever when this whole situation is literally a first for him and the girls, or anyone that could have stumbled upon it. That's like saying soldiers are incompetent when they first experienced trench warfare. They lacked experience so it's natural they died en masse, that's why we had drill instructors and training regime and even those could only kept a small numbers alive, and neither of which are things MC had the luxury to afford before starting this journey.

"Coward MC" when the next chapter clearly showed as to why he's against the idea of someone sacrificing themselves even if it's for the greater good. Sure, tell me you read the story through only your subjective view and speak with bias without telling me.

Black lace.
It's always the glasses girl who wears the most racy underwear, huh.

And you're speaking from the standpoint that all seven of them are simply "components" for you to solve this problem rather than people with actual feeling and emotion, which if we have learned anything at all from the start of this series then their feelings play a pretty critical role in breaking this curse, something that you're completely disregarding.
By your logic if it's as simple as all seven of them just exchanging their marriage vow with him, consent and free will be damned, then all he needed to do is just drug/hypnotize them, ask them to exchange the vow and be done with it. Which, again, isn't how things fucking work as far as this setting is concerned. And again still nothing comes even close to suggesting what you said is a surefire plan. There are merits to it but considering this is a rom-com manga, treating people like just another value in the equation usually if not always never pans out well.
Also, immaturity =/= cowardice.

His idea of love, joy and affection is basically bashing each other's skull in so...

Except in this situation nobody knows for sure what "exchanging marriage vow" even entails and the one girl who offered herself to him was doing it out of desperation and a sense of duty, not out of "seeing the bigger clues" as clearly seen in the next chapter.

So no, he does not lack conviction. He simply does not want to in the spur of the moment do something that can permanently damage both the wellbeing of the girls and his relationship with them in a blind pursuit of this "cure" that they don't know whether it will work or not and their situation certainly isn't one that allows "trials and errors".

What you described is simply mindless sexual urges and honestly just the lowest kind, for you're basically exploiting a woman on her insecurities in order to seek pleasures for yourself. That makes you a nympho and, a creep.

"So he's a slave to the cat."
Egyptian and cat owners: "aren't we all?"

Ah yes, not being an absolute horndog is considered "lacking conviction" nowadays.

They confessed when Okarun was being suck out of the cursed box. Ayase said that's a flag and he can confess to her properly again once the fight is over.

"Yes, yes, Lauralis! Split him wide open!"

It's funny how cultists in literally every form and piece of media assume they somehow have the power to control the Big Bad just because they summoned the Big Bad.

Okay, Miyahara with shark teeth, pretty nice.

Fucking hypocrites, those people. If drawings of 13yos in swimsuit is enough to get you that uncomfortable you feel the need to spell it out for others then it's not the author but those people who need to touch grass and possibly see a psychiatrist.
Like imagine seeing a family with middle/grade schooler kids at the beach and walking up to them saying "the sight of your kids in swimsuit is very obscene. Please cover them up" only thing that would get you is either getting socked or reported to the nearest police officer.

Nah, the book I want most is "How to get your fucking life together for dummies".

"Newly hired maid is suspicious"? Or "Meika can't conceal her feelings"?