Brought to me and X-Blast's attention, we decided to address our thoughts on this matter.
A while ago Alex Hirsch tweeted something along the lines of: "Buckle up folks, at least one character will not survive the season." This was tweeted at the beginning of Season 2. Although there already has been a death, The Mayor of Gravity Falls, but the whole Weirdmagedon scenario and Alex still dropping hints at someone else biting the dust has me convinced someone else is going to croak. So who will it be? First, I'm going to go through who will probably will not die, which starts with Dipper and Mabel. Can you imagine these lovable twins dying? Neither can I. I mean it's sort of an unspoken Disney rule that you can't kill off the main characters or childern. So even if Alex Hirsch wanted to kill them off I don't think he could. They even are based off of him and his sister Ariel and why would you kill yourself off? So these are my two most likely candidates: Stanley and Fiddleford. Why? Because if you recall at the end of Weirdmagedon Part 1, I'm pretty sure there was a decoding that read "Now let's see which of the Pines survive." So this is hinting that 1 of the Pines might die. It can't be the twins for reasons I addressed earlier and it won't be Ford because Bill literally confirmed he'll die of a heart attack at age 92. So that only leaves Stanley. And it would be a pretty good reason that Gravity Falls would be over hence the twins would have to go home and wouldn't want to come back because they lost there Grunkle. Mcgucket is also a candidate because Alex Hirsch has hinted at it many times himself and actually if you think about it, it could make a very sweet and heartbreaking scene.