Ekklesia means gathering of the faithful, not the magisterium. Catholic and apostolic Church simply means followers of correct Chirstian teaching, as passed on by the apostles, everywhere.
No; “apostolic” means a great deal more than what you suggest. It means that the Church is apostolic by character and constitution. The Church is not a DIY project; she SENDS her authorized messengers to proclaim the good news and the sanctify the world through the sacraments. The Church isn’t a polling service asking what the people think they believe.
I can’t believe we’re even discussing this.