I dont know why they say they have no major predators, but Dingos sometimes eat them. I have not found one myself but I have seen photos of wild dog/dingos den sites and they are always surrounded by Echidna skins.
none of the new stories have been very explicit, but from what I can gather the 2012 news (starting off this thread) were babies produced by captive-bred mothers (the fathers being wild-caught) while for these new babies both parents were captive-bred.
New or old, it' none the less an impressive achievement in modern husbandry for this species after years of studying and hard research.