You can’t have Spic without Span.
I wonder how many people who use the term scot free know what scot means.
It’s Mr. Miracle’s first name - who doesn’t know that? 
Wrought is almost always only used with iron or in a purposefully archaic phrasing like “What hath God wrought.” The reason, of course, is because wrought is merely the past tense of work and worked is a much more popular and standard inflection.
Fail it?
How about “petrified” usually being followed by “wood?”
One can be petrified in their tracks.
I will give a loud cheer the next time I hear someone recite of list: things, people,etc. without saying, “last but not least.”
Not so! They are typically used together because, like “boys and girls” they are two classes within the same general type. I will grant that the phrase “flotsam and jetsam” to refer to random assemblages, especially those of dubious value, has had a lot of use.
They actually refer to types of marine salvage and can occur separately or together.
Flotsam is what falls off a ship or is released by action of a shipwreck, and is salvageable by the finder - Finders Keepers.
Jetsam is items intentionally jettisoned (note the similarity of terms) in efforts to save a ship from sinking, and the owner retains title if the item can be located. (Salvagers can get a finders fee / reward.)
love and marriage
horse and carriage
I must have watched Married with children too much.
In certain contexts, “petrified” is usually followed by “adventurers”. Only if the dungeon master likes cockatrices or gorgons, and hates his player party. So, pretty often.
I will simply cite one of the links you provided:
Underlining added. It appears to be you that is misuing the word “grammar”. Not to say that collocation is not a thing, but you seem to be misstating how it works.
From the link, collocation appears to be a larger thing that includes the concept this thread is addressing.
Ulterior and motive.
And here in Montreal, crumbling and infrastructure.
Maybe cuz I’m a certified old fart®, but when I hear the word “Kennedy” I immediately think of the word “compound”.
In California, at least, one seldom sees the word “Lamborghini” in the news without being attached to the phrase “wrapped around a telephone pole”.
“Inclement” appears to have the singular function of describing the weather.
I’ve never heard it used in any other capacity.
Well, you can, but I’d be very careful about using it.
Nm
Halcyon Days.
Grassy Knoll.
God smited.
And one which probably is more of a Brit soccer thing…
Diabolical decision.
In my youth, “Spic” was a vulgar contraction of “Hispanic”, not something you would use in polite company.
Indeed. My point exactly.
I’ve only ever seen it spelt ‘Spick and Span’.