As to Count II.
II. A Christian believer can have full knowledge of a divine law and voluntarily choose to break it in a serious matter, but not be in a state of mortal sin as a result of this action.
– Open Letter to Bishops of the Catholic Church, Easter Week, 2019
FUNDAMENTALS OF CATHOLIC DOGMA, Ludwig Ott > BOOK FOUR > The Doctrine of God the sanctifier > PART 1 The Doctrine of Grace > SECTION 2: Habitual Grace > Chapter 3: The Consequences or Fruits of Justification or the Doctrine Concerning Merit > §22. The Attributes of the State of Grace > p.282:
3.a) Loss of Grace
The grace by which we are justified may be lost, and is lost through every mortal sin. [De fide.]
… De fide …
To hold a position contrary to 3.a) above is to hold a heretical proposition. Therefore Count II. is a heretical proposition (propositio haeretica) or a proposition opposed to a formal dogma [3.a) above].
395. When does one commit a mortal sin?
One commits a mortal sin when there are simultaneously present: grave matter, full knowledge, and deliberate consent. This sin destroys charity in us, deprives us of sanctifying grace, and, if unrepented, leads us to the eternal death of hell. It can be forgiven in the ordinary way by means of the sacraments of Baptism and of Penance or Reconciliation. [Cf. CCC 1857]
Therefore, not only is count II. a heretical proposition opposed to a formal dogma 3.a) above, but it is also a false proposition (propositio falsa), a proposition contrary to a dogmatic fact which in this case is ‘what committing a mortal sin is’.