Is there a reason you can't actually see the PO or the items on it from the mobile beta app? You can mark the PO as arrived and that it may have 4 items on it, but without logging into the desktop version you won't know what those items are on the PO.
You mean showing the expected items and quantities while receiving? It doesn't show on purpose in order to force the person receiving to actually count. Otherwise, it could be pencil-whipped by just inputting the expected numbers. There will eventually be an option to show the expected items/quantities, but it isnt part of the initial release.