My sentiments, pagemakers4 -- almost exactly.
It does seem, however, that clearing all iCloud backups of the iOS devices from the Air, then doing a hard wipe of the text replacements from the Keyboard function on the Air IS keeping the nasties from reappearing there. I cleared that list entirely, even deleting Apple's silly "omw!", so now it's an empty list. This is a marker of sorts for me, because any clean install, guest user, or test user (one was created on the Air during all this tech intervention) pulls up a new basic list of its own, one that includes the "omw!" by default. So, that my Air list staying empty tells me is that I'm controlling the function -- but I still don't know how or why. I'm signed in on the Air, so am tied into the same user ID as I was before. The only thing I haven't done on the Air since the cleanup is hardware the iP to iTunes, and if I have to keep avoiding that, it's going to make photo management unnecessarily complicated.
One other thing that's making this difficult, by the way, is that in all the fuss about aligning functions between the OS and the iOS, making sure messaging and photos all work the same way, etc., Apple hasn't aligned the names of this particular function. In the iOS these are called quite specifically "Keyboard Shortcuts," but on the OS they are under KEYBOARD and TEXT, where one selects "replace" and "with" options, while right in the tab next to TEXT is something categorized as SHORTCUTS (thus, KEYBOARD SHORTCUTS), which controls an entirely different set of functions. So, are these SHORTCUTS, TEXT SHORTCUTS, KEYBOARD SHORTCUTS, TEXT REPLACEMENTS, or what? It's too confusing -- and all we really know is they don't work as they should.
As for the iOS devices, I'm trying the workaround of the Canadian keyboard (yah, eh...), and will see if that works. And I'm still not hopeful, because every time it has seems that I (or any of us) have this figured out, it reverts. It's like trying to nail Jello to the wall.
Sheesh.