Casual EDI should not exist. Sending acknowledgements back to the sender is not helpful so we should not mandate this. Because we cannot guarantee that the receiver actually processes the request even though it was delivered. The receiver can fail due to a number of reasons including, but not limited to, bad programming of the receiver. However, they don't always want to pay for it or can't get it because the infrastructure they use does not provide it in a convenient manner.
Authentication requires data integrity but includes guaranteed identification of the sender.
Leave it up to the user how they want to combine things. This group should focus on a solution that allows the user to pick the elements they need. Why spend time trying to grab hold of different types of EDI, leave it up to the user. Basic, reliable delivery is adequate. No special security required.