Struthio, your below statement is the problematic one. Your use of 'manifest heretic' is not the same as +Bellarmine's. So, your explanation of heresy is illogical.
..They don't "basically agree". Obstinacy of the will is a HUGE factor. One side believed that obstinacy was necessary to lose membership in the Church and the other side didn't. (But that's overly-simplistic, as there are other factors too).
If he's using the term "manifest heretic" in the sense of Bellarmine (and he's not), then he's effectively declaring the Vigano is not a member of the Catholic Church.
There's actually a huge debate among theologians regarding the semantics of the term "heresy". Some held that the term (etymologically considered) inherently denotes pertinacity and so the term does not apply to someone in material error only; in other words, they claim that the term "material heresy" has no validity. If you look at the Greek term, it actually means a "clinging to" something, in this case error. So they argue that lack of pertinacity invalidates the term heresy. It's largely a semantic discussion, which is why someone must define their terms before hurling accusations of heresy.
But then the term "formal" heresy became polluted as theologians started to water down EENS dogma. Initially, the distinction was between the material believes (the what of belief, the propositions believed) vs. the formal motive of belief (they why of belief, i.e. the teaching authority of the Church). So, for instance, it's hypothetically possible for someone to hold every single proposition taught by the Church but still be a formal heretic because it's not believed with the proper formal rule of faith. Conversely, it's possible for someone not to accept a particular proposition of faith while retaining the formal motive of faith, either because a person simply doesn't know it has been defined by the Church or misunderstands something that has been defined. As St. Augustine taught, the litmus test for this kind of material error is the person's willingness to abandon the false proposition as soon as one is enlightened about the fact that it is contrary to Church teaching. When corrected, the person's attitude would be to immediately and unhesitatingly correct the false proposition once the correct Church teaching is explained.
This is also why theologians teach the notion that if you deny one dogma, you deny them all. When you pertinaciously deny one dogma, you are impugning at least implicitly the authority that underlies all dogma, and you lose the formal motive of faith for those remaining propositions that you still happen to hold.
There's no doubt in my mind that Archbishop Vigano intends to accept whatever is and has been taught by the Catholic Magisterium. He, like many others still do, clung to the notion that V2 was a question of ambiguities that COULD be interpreted in light of Tradition, with the hermeneutic of continuity. When someone has this attitude, it's
prima facie evidence that they are not formal heretics, because they belief that everything must be consistent with Church teaching. Heretics don't care whether or not the propositions they hold run contrary to Church teaching.