Would the use of the Cherubim for this role shed light into what was lost on account of The Fall? I have to admit that I have trouble grasping what this could have been.

Would it be possible to think that the intimate relationship that Adam and Eve had with Our Lord, which was broken by The Fall, was so close that Cherubim was needed to sever it?

In fact, the most likely person to have discussed this subject at length is probably my own beloved Seraphic Doctor, who devoted some effort to explaining the different classes of angels (or so I understand). I fear I am not at all familiar with the relevant texts, however, and it would probably be a trick even to get your hands on hard copies of them (which surely would not have been translated from the Latin.) And I wouldn’t make much headway trying to publish on that subject as an academic philosopher! But maybe someday…

St. Thomas says some very interesting things about the roles of the different choirs in his Commentary on Ephesians. Unfortunately, I cannot remember it very clearly and my copy is not at hand.

The Tree of Life is often represented as a type of the Eucharist, though, so you may be on to something there. I believe St. Ephraim gave it great spiritual significance in his Hymns on Paradise.