I'd try again! We got one that was the 1/3 yellow tint on home button side, top was slightly pinkish. It immediately jumped out at me the first time I brought up the keyboard. I was hoping it was something I could live with-- if you didn't look for it, and weren't on white pages.
However, I decided to play screen lottery... And won!! I returned the original one th last day of the return period and exchanged it for another. Fantastic! White screen, no yellow.
If it matters, the original serial # began with an F4LL and the latest good one with DXLM. However, everything I've read says that the serial # isn't key.
One other factor in all this... I do believe that the iOS keyboard with its grey background induces a yellow visual contrast on the white... Those sorts of visual effects are well known. Obviously, what's going on is much more than that, especially given that the keyboard will change colors when you rotate the device--the yellow remains with the home button. Best seen by using a split keyboard.
In any ever, we're just thrilled to have one that isn't showing yellow! (Now, if I could only figure out out to lose the grayish, shadowy, book spine effect on the iPad Air!