This is all speculation and opinion.
No one here is a copyright lawyer. It is nice to have a designer here and thank you for sharing your view.
I have stated my opinion on copyright in other threads so I will not repeat myself here.
But everyone remember that no one here is a lawyer so.
If you want to sell a quilt you make the call.
If you want to risk getting sued (and remember they dont have to win to cost you a lot) then go on with it,
If you have copyright questions ask a lawyer
If its not that big of deal to track down the designer then track them down and ask
If you dont like that the pattern comes with stipulations then dont buy it.
Also even lawyers can argue this case to death.
Just as Mccall's has lawyer on their side saying what they want them to say.
I too could find a lawyer on my side saying what I want them to say.
Until this matter has been handled in a court room it will be gray area.
I have yet to see a court case about patterns that did not have to deal with the pattern its self being copied. Or if it was about the item made it was settled with a gag order so we will never know.
Just one question
if McCall's has all of these copyrighted patterns why are none registered.