Which is cool. But none of this is answering my original questions. Why would it suddenly not be "cross dimensional" in power (especially since we've seen her use it in multiple non-Innistrad places)? Why would we assume the other two dead non-Grisseldaddy demons aren't perma dead (especially if they never had auto-res powers)?
I think there's some conclusion leaping here, is all I'm saying. The reason they pointed this out with Grisselbrand is two-fold. First, they had to find a way to get around the plane's lore with demons auto-resurrecting. And second, it displayed the awesome power of the artifact she was using by breaking the rules on a powerful enemy. Them not mentioning it while killing the other demons doesn't mean they're coming back. They were never established to have that power. Her not needing it on Amonkhet development is a new wrinkle, of course, but that seems to be unrelated to the Veil's functionality and more her connection with some kind of power on Amonkhet.
I do believe demon four is going to cause problems, however.