I'm reading, trust me. I just dont happen to think any of those statements make a character a main character.
Since, according to what you quoted from Rocket, we can google anything for an answer, here is the googled answer of what a main character is:
A protagonist (from Ancient Greek πρωταγωνιστής (protagonistes), meaning 'player of the first part, (chief actor)' is the main character in any story, such as a literary work or drama. ... In those forms the protagonist may simply be the leading actor, or the principal character in the story.
A game without a story of any degree has no main character.
And I do apologize for not starting with that as my explanation from the very beginning.