Exactly. They never put theories into these. They just add characters into different films for no reason. Guessing it's kinda like an Easter egg kind of thing.
I mean, these films are different. The theory sounded okay until 'Boo is the old lady in Brave'.
This is one persons interpretation, and this guy and Disney do not have a similar mind.
Who knows, there could be a connection, however if there was it would make more sense than the other theory. I'm not sure what the connection would be but these people are film making masterminds. They make the bucks with their ideas.
However, I think that the furthest they'd go with connection is adding characters into films (like Rapunzel and Flynn in Frozen, etc). They're too busy making the films to even bother connecting them.