Are they always unanimous or is a majority sufficient.
It is imcumbant on every outspoken critic of the Church to actually know the subject matter before foolishly opining.
There are two categories two categories of Magisterium; the Solemn Magisterium and the Ordinary Magisterium, differentiated by the gravity of their pronouncements. The Solemn Magisterium speaks from the Chair of Peter on matters of dogma.
The Magisterium is comprised of the Pope and the Episcopacy of the Church. The bishops consider an issue and advise the Pope, who with the guidance of the Holy Spirit, then speaks on the issue. It functions today as it always has:
"The apostles and the elders met together to consider this matter. After there had been much debate, Peter stood up and said to them, “My brothers, you know that in the early days God made a choice among you, that I should be the one through whom the Gentiles would hear the message of the good news and become believers. And God, who knows the human heart, testified to them by giving them the Holy Spirit, just as he did to us; " Acts 15:6-8.
Peace be with you