What should happen now to end things off is some random asshole delinquent starts shit with them. Each of them immediately goes "beast mode" to defend the other.
They get suspended for fighting in school, but it's a good thing; it reminds them that their relationship is so precious to them...
Nah, not really. This is like One-Punch Man: they are ironically given everything that some other protagonist could ever want or need to accomplish that other protagonist's goal, but it's irrelevant or an outright obstacle to their comically different goal. Saitama wants an actual challenge...
Depends on where. Cities like Tokyo are so dense that for the most part, having cars doesn't make sense. This is why a lot of people are actually "paper drivers" -- they have the license, so in theory they can drive, but they never get time behind the wheel, so when they finally rent a car to...
"Osananajimi" is a pretty well-established term for the "childhood friend" archetype. https://www.animenewsnetwork.com/encyclopedia/lexicon.php?id=104 It's not surprising if multiple people independently came up with the same idea of splitting it in "Osana" and "Najimi" and making it a...
I think he's buying it for himself; what she's providing as her thanks is her time and expertise. She's pretending like it's an imposition on her to do this for him, although we know better.
The text leaves it ambiguous, at least in this translation, but that's the most reasonable...