The answer is unfortunately, who knows.
While I do often use these times as a reference, there are a lot of instances in this document where the times just make no sense and are clearly a result of the team overlooking some details or the person making these diagrams making mistakes. Like, there is no reason for travel times between Barrie South and Bradford to increase by 10 minutes post electrification.
A similar weird spot also exists on the LSE diagram where for the pre-expansion AM Peak it uses time from Oshawa assuming the express service (which is why time to Union from Pickering is 29 mins, meanwhile its 30 mins from Rouge Hill), however it doesn't do that for post GO-Expansion despite claiming that the same service will still be available.
Not quite. On LSW its past Burlington.
On Kitchener, they actually own the track past Georgetown all the way to Kitchener - and as such they are actually studying electrification for that corridor. What they do not own is the segment between Georgetown and Bramalea: That's owned by CN.
Here's a diagram showcasing all of this.