I want to be involved in this discussion, but I'm not sure I'm knowledgeable enough about either.
Forgive me if I get any of this wrong.
I do think leavened vs unleavened is important. We use leavened bread because it is the body of the RISEN Christ.
Infants not being communed has more to do with them not being in full communion yet?
It may also be that there is a difference in the way in which it is perceived. Is Catholic theology concerned with any re-sacrificing of Christ? Do you speak concerning the details of what the physical substance of the Eucharist is like?
We do speak of the bread and wine being our offering that we bring into the Church, and the Holy Spirit changes it to be the Eucharist for our benefit.
I know that we do not have Eucharistic adoration, though the Eucharist is treated with the utmost respect.
Really though ... trying to come up with these off the top of my head is no good. I would have forgotten leavened vs unleavened if it hadn't been mentioned by someone else (At least I wasn't thinking of it st the moment), and that's probably a major difference, since it was an issue dividing us early on.
I'd much rather see two priests who knew both discuss this.