Plus, you have to remember that all Ford SUV's start with "E".  That right
there limits your name choices dramatically.  Cars all start with "F",
except for the Mustang, which is kind of untouchable.  Mercurys all start
with "M".

Personally,  I think that they're making a series of very dumb moves, for
two reasons.

First, their lineup is very confusing. Especially at Mercury, where both
cars and trucks start with M.  Does anybody know whether the Montego is a
truck? Is the Mariner a van? The Montero is made by Mercury, right? Am I
looking for a Freestar or a Freestyle? I can't remember.  The solution to
the Mustang name mismatch is clear - Just call it the Mercury Mustang and
your problem is solved!

Second, they give importance to renaming their products (badly) which
outweighs the value of what they have to give up.  They had to hurry up and
rename the Zephyr a "MKZ" before the Zephyr built up any brand identity.  As
if that was a BAD THING.  You may have also heard that they woke up one
morning a few weeks ago and realized that the Ford Taurus had been the best
selling car they had for about 20 years, including 2006, when it wasn't even
available to the general public. Whoops!  It's never too late, and they're
going to rename a product Taurus maybe.

I assume it is a case of misplaced priorities.  It would be alarming that
somebody working for the company would be dumb enough to think MKZ to fit in
with MKX and MKY is a better name for a car than Zephyr, and MKX is better
than Aviator, too, just on its own merits.

Anyway, I think Edge is pretty good.  Compared to MKLT, Edge is a very good
name.

Well, to be fair, Mitsubishi is a Chrysler property. The Dodge RAM trucks of
yesteryear were Mitsubishi trucks.

But, I believe you are essentially correct, they have to use the names they
own, or risk losing them. Having said that, I can't imagine Chevy glomming
onto a Ford product name that had fallen into disuse. I'm certain that in
the example you cited, the name was exchanged because the companies share
stuff.