Sorry, this is getting ridiculous. This is what you wrote and which I disagreed with:
No, neither of those cars has a "mostly vertical opening starting at near the peak roof-line of the vehicle", and certainly not the Citroën 11CV, unless you consider 65° "mostly vertical".
The Honda Civic example you cited is particularly ridiculous:
Yes, it has a vertical part as pretty much any vehicle that has a rear, and no, it's nowhere near a mostly vertical opening starting at the "peak roofline" of the vehicle - half of it is angled, half of it mostly vertical.
Nor do 99.9% of people who use the term 'liftback' know what 'flow detachment means', let alone are able to tell where it occurs. They use the poorly defined term "liftback" for a modern hatchback that doesn't look too boxy in the rear. Over 95% of modern hatchbacks are such.
Manufacturers started using the "liftback" term mostly for marketing purposes, to deassociate modern, more streamlined hatchbacks from old hatchbacks that look ugly.
It's not a technical term. If you search for "hatchback vs. liftback" one of the top hits is going to be this:
Which is what I was trying to stress from the very beginning: it's semantics and cultural. It doesn't matter, and
nobody uses the flow detachment definition in any case ...
I do agree that whatever hatchback/liftback Tesla is going to design, it will have an excellent Cd with minimal flow detachment.