If you picked a winning pixel, but didnt check on it for awhile and someone else picked that pixel, would they recieve the winning message or is that your pixel now which means you can take as long as you want to, to enter your personal information?

no. the winning pixel is canceled as soon as it is  discovered, so no one else can win it

good question
because, after clicking for hours, I usually do one last click, go away, and return after hours to check whether I've clicked a winning pixel

but AFAIK, patchou said that he'll contact everyone who's clicked a winning pixel even if they didn't fill out the form correctly / are so shocked by clicking a winning pixel that they accidentally close the window

I'm glad to read this