Where did 'cahoot" come from, when did it first appear, and how did it acquire its pejorative sense?

From The Collaborative International Dictionary:

• Cahoot Ca-hoot", n. [Perhaps fr. f. cohorte a company or band.] Partnership; league; as, to go in cahoot (or in cahoots) with a person. Usually used in the plural, and in modern usage often used to imply that the joint effort is unethical, shady, questionable, or illegal; as, a shill in cahoots with a pickpocket, to serve as a distraction. [Slang, southwestern U. S.]
  --Bartlett. [1913 Webster +PJC]

Grammarphobia looked into it but came to no clear conclusion. I think the extract is worth your attention anyway:

The origin of Cahoot:

There are two theories.

• The one favored by the Oxford English Dictionary is that English got the expression from the Scots, with a little help from the French.

• The OED says the “cahoot” in the expression is “probably” from the French cahute, meaning a cabin or a poor hut. The French word, with the French meaning, was adopted into Scots English in the 16th century, but “cahute” was short-lived in English and is now labeled obsolete.

• The OED’s only two citations for the usage are from the 1500s (the earliest is a 1508 reference to a “foule cahute”).

• The word (if indeed it’s the same one) reappeared as “cahoot” in early 19th-century America, where the phrase “in cahoot with” meant in partnership or in league with.

• The OED’s first citation for this sense comes from Chronicles of Pineville, a collection of sketches from the early 1800s about backwoods Georgia, by William T. Thompson: “I wouldn’t swar he wasn’t in cahoot with the devil.”

• The second quotation is from Samuel Kirkham’s English Grammar in Familiar Lectures (1829): “Hese in cohoot with me.” (Kirkham lists it among provincialisms to be avoided.)

• And the next, with the usual spelling, is from the Congressional Globe, predecessor of the Congressional Record. It’s from a speech delivered by an Ohio congressman, Alexander Duncan, on the floor of the House in February 1839:

  • “Only think of this! A rank Abolition Whig from the North in ‘cahoot’ with a rank anti-Abolition Whig from the South.”

• The word “cahoot” apparently continued to be used in the singular for a couple of generations.

• The OED’s first citation for the plural “cahoots” is from a manuscript diary of G. K. Wilder (1862): “Mc wished me to go in cahoots in a store.” And “cahoots” it’s been ever since.

• The OED’s etymology makes sense, because being in on a scheme with someone is like being holed up in the same small cabin—much as we might use “in the same boat.”

• There’s only one problem with this explanation. Where was “cahute” or “cahoot” for that missing 250 years or so between 1553 and the early 1800s?

As it happens, there’s another theory about the source of “cahoot.”:

• The OED notes that others have suggested an origin in the French cohorte, the source of the English “cohort,” which originally meant a band of soldiers.

• But apart from the resemblance between “cohort” and “cahoot,” we haven’t found any evidence that would connect the dots and support that theory.

• This leaves us a bit up in the air. But we’d like to think the OED is right, and imagine people “in cahoots” (old coots, perhaps?) as hiding out in a grimy hut and plotting together.