Some predictions for the upcoming P&F movie (ranging anywhere from "will almost definitely happen" to "not likely but I'm throwing it out there anyway"):
One of the brothers turns evil
Candace and Jeremy never officially get together
The timeline is mostly put back to normal at the end, but some things still get permanently changed for the rest of the show
Ferb talks more without Phineas to do it for him
Alternatively, Ferb never talks at all until he reunites with Phineas
Perry lives with a different family and doesn't like them
Doof and Perry have never met
Phineas and Ferb get sidelined somehow (I will be REALLY pissed if this happens)
Isabella never gets a crush on Phineas
Isabella crushes on someone else (gasp!)
Irving becomes a fan of someone else
The rest of the Backyard Gang are all worse off in some way
Flashback to Phineas and Ferb's first meeting (please please please)
Sweet wholesome brotherly moments (please please please please please)
Something gets retconned and the fandom is divided on it
Danville as a whole is worse off without Phineas and Ferb
Super cute Linda and Lawrence scenes
Phineas has some kind of breakdown like in SBTY
Some hidden depths are revealed for one or both brothers and fanfic writers obsess over it for months
Someone is surprisingly better off even though you'd think they wouldn't be (it's played for laughs)
One or both brothers have a different pet
The kids team up with Doof again (since he's the one who caused this mess)
The kids encounter Agent P and shrug it off as some weird alternate timeline thing
We find out how Candace met Stacy and/or Jeremy
We find out how Phineas and Isabella met
Phineas's dynamic with Candace is really different without Ferb around
Building a rollercoaster is important to the plot somehow (since that's where everything started in the original timeline)
Phineas and Ferb remember each other as soon as they meet
Or, Phineas and Ferb don't remember the original timeline but still figure out that something is wrong
Official confirmation of which brother is the older one
(Feel free to throw your ideas out there too)
