Also Walts got cancer again, thats why he punched the bathroom up and payed Jesse.
I think it's pretty much guaranteed, considering how long they lingered on the shot of him on the scanning table.
Possibly but Gilligan is not above having a go at the audience, or at least messing w/ expectations. I'm sure he had a nice laugh about the reaction garnered from Walt and Jr. watching Scarface, and Walt saying "Everyone dies in this."
Then again, the flash forward had Walt coughing and taking pills, so it wouldn't surprise me if things come back full circle w/ the Big C taking Walt out after all he's been through. Irony, she is cruel.
The "Everybody dies" line was apparently ad-libbed.
And in case you think Cranston knows how the series will end, he doesn't. All of the actors find out what's going to happen when they get the scripts, and they get the scripts when they are actually going to start filming.