DR, in that quote from Etsi Multa there is no definition of "the Church." And its subject matter is not about defining the doctrine of "indefectibility of the Church." It mentions the concept of "indefectibility of the Church" in relation to the specific situation of the Old Catholics and their criticisms of the Roman Catholic Church.

Etsi Multa states that those specifically referenced, the Old Catholics, had denied "the indefectibility of the Church." Those offenders, the Old Catholics, were claiming that "the definitions" that came out of Vatican I were heretical "definitions." So the Old Catholics were suggesting that the Roman Catholic Church had "defected" from the ancient, immemorial faith and this "defection" justified the actions of the Old Catholics to separate and form their own Church.

Of course Pius IX is condemning the Old Catholic heretics and schismatics. He, Pius IX, is doing so from the perspective of someone who holds "the true faith." Pius IX famously said that he "is the Church," and in saying that he was simply stating, in a slightly different way, what Pius XII said in Mystici Corporis, that "the Church" is made up of those who "profess the true faith."

Now, moving forward to Vatican II, you seem to be suggesting that when a traditionalist says that certain propositions of Vatican II were heretical, that the traditionalist is doing the same thing that the Old Catholics did. But that is not correct. The traditionalist continues to "profess the true faith." The traditionalists are playing the role of Pius IX.  It is the heretical members of the institutional conciliar Church, the infiltrators, who were playing the role of the Old Catholics in the post-VII era. But they were now doing so from inside the Church rather from outside the Church as the Old Catholics tried to do.

Your second quote poses no problem for the doctrine of the "indefectibility of the Church." First off, it is from a draft docuмent. Why are you even quoting it as if it is the official teaching of the Church? Second, what does "governing body" mean exactly? Is a bishop not a person who represents the "governing body" of the Church? You seem to jump to an interpretation of those words to mean the full world-wide diocesan structure of Church government. But, you have to admit that you are reading that interpretation into those two words aren't you? Still, the statement is not magisterial, so I don't know why you are even quoting it.