I agree with much of that, but, I think 2012 - 2020 is far too much Time.
The problem is that Rory says he's 31 in "Dinosaurs on a Spaceship." We know from "Let's Kill Hitler" that he's Amy's age or younger, and we know that Amy was born in 1989 since she was 7 in 1996.
Granted, this is subjective, but I don't see how Rory could accurately calculate his subjective age including time spent traveling through history with the Doctor. So I took that to mean that he's 31 relative to the Gregorian calender followed by his family. Add to that "The Power of Three"'s scene where Amy says she and Rory have been adventuring with the Doctor off and on for ten years, and that leads me to interpret Amy and Rory as being from the early 2020s in Series Seven.
None of Season 5 was written out of existence. The Big Bang restored practically everything.
But it also wrote the Cracks out of history; the Cracks never happened. So that shunts the timeline in which Amy grew up without any parents -- in which she met the Doctor when he encountered Prisoner Zero -- into an alternate timeline. Amy remembers both timelines (as established in the Night and the Doctor
mini-episodes) simultaneously, in the same way that Rory remembers both the timeline in which he was an Auton for 2,000 years and the timeline in which he first met the Doctor at his wedding simultaneously.
The Doctor called in favors from people from season 5 and 6 to help in AGMGTW, including Churchill,
He had a prior relationship with Churchill, so that doesn't necessarily mean anything.
However, we also know from Series Five that memories and consequences can continue to exist without causes -- Rory still being in a photograph and Amy's engagement ring persisting even after Rory was erased from history, for instance.
I recall no reference to Queen Elizabeth X in "A Good Man Goes to War."