Hi snowbunny (cute name),
Im not an expert in this sugya, but from what I understand R’ Moshe was posek the way that he did BECAUSE of the stuff you listed in #3. Also, we still need OU-D, because when you live in a place where there is no chalav Yisrael (or if it is outrageously expensive), then you are allowed to eat chalav stam. Not only that, but if you are noheg to eat chalav stam in your town where chalav Yisrael is hard to come by, and you travel to New York, for example, where CY is readily available, you are still permitted to eat chalav stam.
Feel free to correct any misinformation I may have, anyone.