I am a native speaker and have regularly used hyphenated phrases in both professional and academic writing (though, to be clear, that does not mean that my answer is necessarily correct). I don't claim any formal credentials in English punctuation.
First off, if your school has a preferred style guide (like the Chicago style linked in your question), then use that.
As for what "looks right", this is a weak standard because hyphen use is wildly inconsistent in day-to-day usage among many native English writers, and even for specific writers. Worse, usage has changed a lot over time. So, unless you have a reader who really cares about this, you are unlikely to be called out on your usage as long as you are consistent (and you are not ignoring an existing standard, like the Chicago style, that your school requires).
My major suggestion for you is to try to condense your phrases so that you don't have so many words that are affected by a non prefix at once, as I think this is what is giving you trouble. If you can't reduce the number of words you are using, additional hyphens can add clarity (and follow the Chicago style guide, to boot).
Your cases (1) and (2) are easy to understand, whichever hyphenation standard you choose.
Conversely, for (3) I'm unclear. Including cash flow suggests to me that a person hedges, and they use either cash flow or non-cash flow vehicles to carry out those hedges. But, to my eye, there is no obvious deconstruction of the phrase or delineation between it and surrounding words, and this will always make something like non difficult to parse until the reader is very familiar with your terminology (no matter where you position the non).
For (4.1), if hedge accounter is a single unit, then hedge-accounter might be the preferred style (under the Chicago manual, this would be a noun + noun, and is hyphenated). This makes obvious that the two words describe a single thing, and a non-hedge-accounter is similarly clear. (4.2) is similar to (4.1), in that it is clearer when hedge accounting is understood to be a single "thing" (Chicago style: it is the adjective form of a noun + gerund, indicating a user or non-user of hedge-accounting).
Please note that, due to the widely differing usages, I am not saying that these are the interpretations you should expect from everyone, but rather that the lack of clarity is due to the complex, compound nature of the phrases you are using. Confusion over non is an expression of that, not the source of non-clarity.
I, personally, generally prefer the non-x form to the nonx form, as it makes the word being modified by the prefix very clear and does not give the appearance of a "new word". In the preceding paragraph, I used non-clarity to make obvious that I intended the opposite of clarity, while the word clarity might not be as easy to pick out if reading nonclarity. But this is more style than practicality for me; I rarely (though still sometimes!) have trouble with words like nonnegative.
