Harrison VS Mack
There are thousands of tunes out there lets face it and ok there is a bit of a similarity but perhaps it was just a subconscious memory that triggered the Harrison song, maybe it was a group consciousness thing? I'm not convinced he stole it and I'm not convinced that it wasn't a very attractive proposition to extract a bundle of money from the Beattles!

Lebbeus Woods vs 12 Monkeys
Absolutely Mr woods has a case. How many chair designs are out there and Terry Gilliam has looked at the picture, not only is the chair the same but the ball suspended beside the chair is similar to the TV ball in the movie. I would feel the same indignation Mr Woods felt.

Keir Smith
I guess technically yes his work is a collection of iconoic images pasted one after another. These are all icons we see regularly but they obviously belong to the companies they represent and perhaps they would have a case, but also its advertising isn't it? If its a parody, and it may be considered a parody perhaps its not illegal?
Its entertaining, like the industry it has used for imagery.