I fail to see how any of this discredits the standard solar system formation model and validates Velikovsky.
The oxygen suggests that comets may have formed later than is postulated by the standard model. It goes along with evidence from other comet studies that shows them to consist of a mix of materials that could only have formed under widely varying conditions, and so poses big difficulties for the standard view of comet formation.
Velikovsky's view, which comes more and more into accord with what we know of planet formation in exo-solar systems, is that collisions with gas giants may be responsible for the formation of certain astronomic bodies. Gas giants like Jupiter are viewed as "pristine samples" of the original solar cloud, but their descending layers allow for the formation of materials under varying conditions. Given that the orbits of many short-term comets coincide with Jupiter, it seems only sensible to ask if they might have originated there.
All of this is out of the ballpark of the standard model, and well in the ballpark of Velikovsky.