OK, closing.

Reopen.

GG5: どすのきいた声で in a deep, threatening voice.   (other JEs have it too.)

As I commented earlier, I'm not keen to break with the references and have a 和語 like this lead with katakana. I'll close it off to shorten the queue, and reopen it for a while in case anyone else wants to comment.
Possibly sense 2 can be adj-no?

@@ -19 +19 @@
-<s_inf>from 脅す・おどす</s_inf>
+<s_inf>from 脅す</s_inf>
@@ -24 +23,0 @@
-<xref type="see" seq="2002480">どす黒い・どすぐろい</xref>

Carrying a knife　（image search for "ドスを持っいる" returns people with knives. So does "どすを持っいる", but the captions are all katakana ドス）:
短刀を持っ	818	61.9%
ドスを持っ	504	38.1% (this is not MS-DOS)
どすを持っ	0	0.0%

脅す sense:
ドスの効いた	10642	39.3%
ドスのきいた	7718	28.5%
ドスの利いた	6086	22.5%
どすの利いた	1372	5.1%
どすのきいた	808	3.0%
どすの効いた	482	1.8%

Wikipedia page on 短刀. ドス is used, どす is not.
また、昭和前期まで博徒やヤクザの伝統的な喧嘩道具に使用された粗製の短刀を隠語で「ドス」と称し、金に困った一部の包丁鍛冶などが作ったと言われている。ドスの中でも長い物（1尺8寸超）は特に“長ドス”と呼ばれる。
https://ja.wikipedia.org/wiki/短刀

Video: ドスと短刀って違うもの…？
Video title and *all* comments(a bunch) use katakana form
https://www.youtube.com/watch?v=jIiedTCIgfM

Search どす 短刀, google asks:
Did you mean ドス 短刀?
Comp "どすと短刀" (2 hits) "ドスと短刀" (a couple pages)

Wikipedia disambiguation for DOS. ドス does not appear anywhere
https://ja.wikipedia.org/wiki/DOS

MS-DOS, ドス appears exactly once in the phonetic entry, and not even stand-alone: MS-DOS（エムエス-ディーオーエス、エムエスドス[2]）
https://ja.wikipedia.org/wiki/MS-DOS

Same story for DOS alone. ディスクオペレーティングシステム（英語: Disk Operating System、DOS、ディーオーエス、ドス
https://ja.wikipedia.org/wiki/DOS_(OS)

Summary - from what I can find, at least, it appears that [1] and [2] are far and away predominantly katakana. For [3], hiragana wins out, but not by a huge margin, and [see=どす黒い] removes that ambiguity. [4] is very different from the other terms, and has a restriction already.  Counts don't appear to be influenced significantly by DOS/MS-DOS. [2] generally dominates the other counts, [1] is relatively rare in general. (should these be re-ordered?). Note, for example, 短刀 gets a whole wikipedia page, on which ドス get's a short paragraph.

yourei examples are all (or almost all) 脅す　sense.

==
I changed the ドス /どす ordering after editing ドスのきいた.  I won't post the long list, but if you do an n-gram search for the top 10/100 entries for 
ドスの 
and
どすの
You'll see that first, the list is absolutely overwhelmed by the 脅す meaning(using 効かす・利かせる and even the mistaken 聞かせる), and second,  ドス is the dominant form.
ドスを and　どすを are similarly overwhelmed by a grammatical variation of the same structure.

For the knife, while even sankoku lists primarily under どす, I suspect this is a reflection of it being a "native" and historical Japanese word. I don't know if they would ever handle such a case with ドス(「どす」とも書く).

It actually appears rare that ms-dos was written as　ドス. the wikipedia page for ドス doesn't even list DOS or MS-DOS as disambiguation options. Google "ドスソフト" or "ドス・ソフト" or "ドスのソフト" and you get almost nothing. Replace with "DOSソフト" or "DOSのソフト" or "MS-DOSソフト" and you'll get results. It seems the trendy thing for Japanese people to do might have been to use the English acronym, like DVD etc.

I'm not convinced ドス should lead. The JEs don't have it and most kokugos don't mention it. I think it's possibly noise from DOS.

@@ -5 +5 @@
-<reb>ドス</reb>
+<reb>どす</reb>
@@ -8 +8 @@
-<reb>どす</reb>
+<reb>ドス</reb>
@@ -18,2 +18,2 @@
-<xref type="see" seq="1238070">脅す・おどす</xref>
-<s_inf>derivation of 脅す・おどす</s_inf>
+<xref type="see" seq="1238070">脅す</xref>
+<s_inf>from 脅す・おどす</s_inf>