Don't know about 'inconsistent'. There were witnesses to the 'words of institution', who actually wrote down what they saw, within their lifetimes, then passed on what they saw to their followers. Those followers taught their followers, who became the first of those we Catholics now call 'Doctors of the Church'. Iranaeus, for example, was a student of Polycarp, who himself was a student of John, the youngest of the Twelve Apostles. So those men who created what many call the 'Traditions' of the Church, were only a couple of generations removed from Jesus, so had full knowledge of Him, and His teachings and sayings, even those that may never have been written in the Scriptures.
Those who wrote Genesis, on the other hand, though truly inspired by the Holy Spirit, were a couple of thousand or so years removed from Adam and Eve. Though we believe they wrote what God wanted us to hear, we have to interpret it, because the writers are not contemporaneous to the events. There are, for example, a couple of different ways that Creation is described. That doesn't mean the story was made up from whole cloth, neither does it mean we have to take it literally, in the sense of 'days' meaning the 24 hour cycle we know today. It DOES mean that God created everything, and something in every human longs to return to Him. We, as Christians, strive to live in the way Jesus taught us, so we'll be with Him, when we depart this life.
Wrong. People didn't write the Torah at all. G-d wrote it (according to a midrash, "974 generations" before the Creation). G-d then dictated these words to Moses, letter-for-letter. This is the immemorial Sinaitic Tradition which you pseudo-traditionalist Catholics reject because a bunch of late nineteenth century German atheists came up with theories to discredit it.
Everything has to be "interpreted," not just the first eleven chapters of Genesis. That Catholics choose to interpret one thing literally and another non-literally merely shows their hypocrisy to the entire world.
You are also ignoring the fact that it isn't just the "hexameron" that Catholics reject, but the entire first eleven chapters of Genesis: Cain and Abel, Metushelach, Noach's Flood, the Tower of Babel--everything. According to Catholics and liberal Protestants, when one comes to Genesis 12 suddenly mythology morphs into history.
What G-d said is true, whether or not anyone else was there to confirm it. You don't think G-d is trustworthy?
I think Catholics cling to a literal interpretation of the "words of institution" only because it ticks Fundamentalist Protestants off rather than out of any principal. And it seems to me more and more that this is so.