～でいい (or ～で大丈夫, etc) is an expression that means "～ is acceptable (if not ideal)". I think this is something you can learn by rote. See:
What is the difference between それでいい and それがいい here?
Maggie Sensei: Noun + で(も）いい VS +がいい
So the literal translation is:
If I'm acceptable (to you), let me join the club.
And the implication ...
交差点 only refers to "a place where two or more roads meet". Pedestrian crossings are called 横断歩道. Many 交差点 have 横断歩道, but they are not synonymous.
交差点 safely encompasses small ones, but I think Google Image Search mainly shows larger ones with 横断歩道 for two reasons:
Simply, small 交差点 are are rarely discussed in the news or in politics.
交差点 does tend ...
礼楽 is a fairly uncommon word. It's not very nice to use such a difficult word to explain the meaning of an easy word... Anyway, here its meaning is more of "ritual/ceremony and music" rather than "ritual music". So it's one of the compounds that just mean "A and B", such as 男女, 天地, 山河, 妻子, 文武 and 見聞. Music played by a 堂 doesn't ...
A pedestrian crossing or crosswalk (American) is a point where two lines intersect: a road and a designated area people can cross safely, sometimes invisible but can be physically marked.
A crossing, junction or intersection (American) is also a point where two lines intersect, a road and another road.
And when I look on google images for 交差点 I mostly see ...
The statement "今日は大学の講義で日本状の経営について学んだ。" just doesn't sound right to me and I'm a native. I can see what it wants to say, but it just isn't right. Is this on some sort of textbook? Where is this from? At least it certainly isn't something a Japanese person would write. You are right to suggest 式.
Alternatively, 流 (ryu) would work too.
This オチ is "(unfavorable but easily expected) outcome" rather than "punchline". In particular, ～のがオチだ is a common set phrase that means "Surely it'll end up (something bad)" or "(Something bad) is all you can expect". See the second definition here, and the following monolingual dictionary definition.
ほど means "to the point where ～", "enough to ～". In this context, it refers to the previous line.
表に出す means "to publicize" or "to show something in public". 表に出してはならぬような声 is "the voice that must not be heard in the public", and it should refer to that "Fuwaa".
Check the difference between 気になる and ...
First, please double-check the terminology. It appears to me that the non-bolded part is written in the third person's point of view, and the bolded part is in the first person's point of view. The narrator is a "third person". So this passage has a temporary shift from the third person's view to the first person's view.
Next, the bolded part is ...