@Mike I've had a look at several of the Callery pear trees near the reserve in north Watson, and they do have a few hairs along the leaf edges, but not at the tip - and not nearly as many as in this Manchurian Pear. But it is not an all or nothing situation, unfortunately. So the only other thing is the persistence of the calyx on the ripe fruit in Manchurian.
Having seen it in the flesh, I think it is a Prunus. Leaves have serrated edges which I cannot see in your photos, the leaves are quite thin, not fleshy, and there are occasional spines. Don't think it matters which Prunus. If you think it does, will have to leave one somewhere to flower and fruit. Hard to do when they are in the slashed zone. We have previously recorded P. cerasifera in this area.