Papal infallibility is at the heart of the schism between the Roman and Orthodox churches. Papal jurisdiction and infallibility are directly addressed in Vatican I and thus any discussion on papal infallibility must address the decrees of this council on the nature of the papacy. Indeed, the parts of Vatican I which you posted above make it very difficult to reconcile the Orthodox and Roman Catholic positions.
The question of papal infallibility was addressed in great detail in Vatican I in terms which leave little room for doubt of papal primacy and the nature of that primacy. Vatican II made an attempt at ecumenism. Incidentally, the dogmatic constitutions of Vatican one such as Pastor Aeternus are quite a contrast to the decrees of Vatican II aren't they? Nevertheless, according to the Roman Church, Vatican I's statements meet the criteria for infallibility, while most of Vatican II's do not. Anyone who is Roman Catholic, presumably even a pope who wanted to deny his own primacy to help reunify the Orthodox and Roman Churches, would ipso facto anathematize himself because Vatican I infallibly decrees otherwise. How the Roman church and Orthodox can reconcile this, I do not know, but it appears that one side must give completely way to the other.
“How the Roman church and Orthodox can reconcile this, I do not know, but it appears that one side must give completely way to the other.”
I don’t know either. But for Vatican I, I think it would be quite easy, frankly. Orthodoxy won’t buy into Vatican I. I think everyone, from +BXVI on down understands this. On the other hand, I understand the Roman system about its dogmas the same way you do. Given the clarity of the Vatican I anathems, it seems that any move away from their clear expression would mean anathemazation. I’ll comment, however, that +BXVI has said that Orthodoxy cannot be expected to accept anything more of Petrine Primacy than Orthodoxy accepted before the Great Schism. Now unless he was just fooling with us, I have to assume that he and the Orthodox hierarchs don’t see Vatican I as being the insurmountable obstacle that you and I see it as. Why they don’t is a mystery to me but I have to believe they all have better things to do than just flap their gums at each other.
The Vatican I dogma on papal infallibility locked the doors and threw away the key. It made the separation of Orthodox and Catholic Churches real and final. It was a single offending act that practically assured true reconcilliation will not be possible without one side, as you say, giving in completely and – as someone once said [not so] eloquently – "that ain't never gonna happen."