Welcome to the forums quietsound ( is that synonymous with SBD? )
Don't know about your rights with the dealer, their not going to spring for a job they can't charge back to Ford. You might have some luck dealing with Ford.
I had Mazda problems (related to ford) and they fixed me up good, then sent $250 gift certs in the mail. That was dealing with the US headquarters.
Then my wife had problems with timing just like yours on her Chrysler PT. They wouldn't budge till the service manager called my wife stupid.. I took it from there. They fixed her up good and apologized as well. If it wasn't for the warranty issues we wouldn't go to the dealers or shops at all.
With all that said, what exactly do you mean by "...rear suspension either repaired or the system replaced..." ??
Blown springs? Blown Compressor? Height sensors?
I don't see how the extra weight from people in the 3rd row could kill the suspension.. maybe pop off a loose hose??
Back to that dealer issue, and how they charged back the Mfg'r... With the PT, those clowns showed me one of the original invoices for parts and labor (free under warranty to my wife) that they charged back to Chrysler, it had 1/2 Shafts (both) on there, parts and labor, charged back to the Mfg'r. The 1/2 shafts were never touched !!! The car was there for premature brake pad failure that first time.
Anyway, what I'm getting at, maybe an air line IS and ALWAYS was too short and some kind of irregular condition causes it to pop off. They reconnect the short line (still too short) and charge Ford for the "whole system".
Just an example, but I'm Italian so it just comes to me like that
Some diagnosis processes:
http://www.americanairsuspension.com...NAV%20AREA.htm