Sorry for the late reply. I haven't been playing MCCE PS3. 4J indicated they won't be back until next year and as it is, it's unplayable for me.
I don't think it's any particular class of trade villager; I have been moving the older ones to a 'retirement village' and noticed the new trades in a couple of them, so I don't think they are the same class.
I will check after the next update, meanwhile- back to PC version.