Yeah, I wouldn't put much (If any) stock into what Universal Core posts. If they were to do something with the Potter expansion that has been explained here, I seriously doubt they would use the entire Tram loading space just for the train station. I wager they would probably use half of it if this is true.
The Monsters taking over Springfield rumor I am absolutely calling BS on. Whatever takes over Springfield is going to be a quick-and-dirty overlay to something generic (Or non-IP specific). Fast and Furious is going right where AA and SES were. That's going to intrude right in the middle of the Monsters village if that's what they're turning Springfield into. Plus, like Clive said, you really want two Kuka arm rides right next to each other? I'm gonna bet good money that Springfield will be turned into a generic LA street. It would fit in with the F&F coaster and leave flexibility for a standalone ride to go where Simpsons is. I could see something like a Bad Guys roller coaster to go where Simpsons is as that could fit with the timeline that could be met before the Olympics start.
That's not to say I don't want any Universal Monsters representation at the park. I would love to see some version of Monsters land over here, but I think the format would be far more suited for an indoor coaster over here.