Some questions from a book on The Beatles

[pink dragon]

Could anybody answer my questions from a book on The Beatles?
After the memorable premiere of the film at the London Pavilion， which clogged up all of Piccadilly Circus on July 17， 1968， John， Paul， George and Ringo have continued to speak fondly of Yellow Submarine.
Q1: Does ‘all of Piccadilly Circus’ mean ‘everywhere in Piccadilly Circus’? So, does ‘clogged up all of Piccadilly Circus’ mean ‘there were too many people in everywhere in Piccadilly Circus and they couldn’t move’? I’d like to make it sure, because if you say ‘all of …’, it sounds like (to me) there are some places called Piccadilly Circus, and all of them were clogged up. Are ‘all of Piccadilly Circus’ and ‘everywhere in Piccadilly Circus’ same?
Until the film's re-release in 1999， the Yellow Submarine had been subjected to several ownership disputes， which kept it from wide video release. “There was a tremendous complication with the music， because some of it was Lennon and McCartney or it was Northern Songs， some of it was that other publishing company， and they could never get together and sort that out.
Q2: Does ‘get together’ mean ‘meet’ or ‘reach agreement’ in this case?
THE TIMES THEY WERE A CHANGIN'

Q3: This is the title of a chapter of the book. Since there is ‘a’, I guess ‘changin’ is a noun, but I can’t find it in dictionaries. Does it mean ‘something/someone that is in the process of changing’?

[Casiopea]

Q1: Does ‘all of Piccadilly Circus’ mean ‘everywhere in Piccadilly Circus’? So, does ‘clogged up all of Piccadilly Circus’ mean ‘there were too many people in everywhere in Piccadilly Circus and they couldn’t move’?

Yes.

Q2: Does ‘get together’ mean ‘meet’ or ‘reach agreement’ in this case?

Meet (so as to reach an agreement). They were either too busy to meet or they used that excuse so that they didn't have to meet.

THE TIMES THEY WERE A CHANGIN'

Q3: Does it mean ‘something/someone that is in the process of changing’?

Yes.

[pink dragon]

Casiopea, thank you very much!!!

[Casiopea]

You're most welcome, pink dragon. Sorry for the late reply.