I had made a villager be a librarian and fully leveled him up to lv 2 to lock in his trades, then had him become a zombie so i could cure him and get trades at a reduced price like in the java version. Once he was finished curing he stayed with the librarian skin and even his title say librarian but his trades are that of a stone mason and even accepts the stone mason trades. This was on friends realm don't know if that matter or not but just so it known