Although the words you listed are all semantically related, they each have quite distinct grammatical roles in the typical usage (with little overlapping) that you never want to miss.
As function words: 自分/己 vs 自身/自ら vs 自己 (vs 自)
自分 is a standalone pronoun that substitutes the same referent (noun) that appears in the context. While it certainly can be ...
In most situations, including ordinary business exchanges, they are completely interchangeable. Maybe 半 is a bit more common in casual conversations simply because it's easier to pronounce, but saying 30分 is always safe.
30分 is preferred in formal written text and technical contexts where consistency and clarity is important, but I guess "half past 3&...
Using 悪くならない for food is a stable choice that means "don't spoil". But just in case, it is not an exact replacement for 日持ち, as the word is a noun "capacity of lasting long" (no derived verb or adjective usage). What replaces 悪くならない as a whole is 日持ちが良い or 日持ち（が）する.
悪くならない保存料 would mean "preservative that doesn't let (food) spoil&...
It's read りょうきん (fee)・うけとりにん (recipient)・ばらい (pay)・ゆうびん (mail).
Yes, it means you can send the postcard without a stamp and the recipient will pay the fee. You can read about this service here: https://www.post.japanpost.jp/send/fee/how_to_pay/uke_cyaku/index.html
All Japanese quantifiers are adverbs. 全部 is an adverb too, meaning "wholly" or "entirely". That means, it is true that it can be ambiguous like "Are the windows all shut?" between "all windows" and "completely". That said, the "all of" reading usually prevails, and also the most common way to say &...
This might not be the most complete answer, but I might be able to give a general picture for what they are used for. I'll give a summary of what I have read, mostly which comes from goo.ne.
自分 - This refers to the "self" in both the concrete and the abstract. For example 「自分の体」refers to your physical body. 「自分の考え」is also perfectly valid.
Asking general feedback is off-topic on this site, but the last paragraph contains a question that can have a clear answer.
"Other than taste and how long until you can't eat it, there aren't a lot of good things about food additives."
The part "there aren't ... additives" is the main clause of the sentence, so you must say this part in ...
痛み is the general term to describe pain or hurting, whereas 疼き describes a more specific throbbing or pounding type of pain. Examples given by Weblio (Japanese) are a pounding tooth ache (or bad tooth) or scar tissue pain.
Do these guidelines for choosing の/こと apply to the use of ということ and というの? If so, those guidelines don't seem to be followed in a lot of the example sentences I've read.
In the sense that you should keep collocation with predicates, basically yes. In the sense that you can add という, no.
Am I overcomplicating this? I've read and heard suggestions it's as ...
I think you have already listed all of the common and not-so-common ones.
あ い う
ア イ ウ
一 二 三
イ ロ ハ (usually katakana)
甲 乙 丙 (explained here)
1 2 3 / A B C / a b c / I II III / i ii iii
These letters are often enclosed in parentheses or circles.
イロハ is still widely used in legal documents, dictionaries and such. It's at least much more common than 甲乙丙. You ...
Unless you want a very strict analysis on the differences of the two, it seems to me that both mean almost the same thing when used to mean "let alone". もちろん is used more often in speech while もとより sounds more formal/stiff and can also be used in written texts/書き言葉.
A simple google search of the difference seems to agree that the two are pretty ...