In which place are you seeing Onyxia Tooth Pendant when you think you shouldn’t? I don’t see it in e.g. the dungeon upgrade finder search.
If you want to exclude specific items from Best in Slot because you e.g. haven’t done a specific quest, etc., you can do it by clicking the exclude button:
Do you know if Ivus the Forest Lord actually drops loot at this phase? Comments on the internet say that at some point they changed it such that those bosses don’t drop loot… just not sure when.
If found in internet, that is the only one source of that Vambrances and they should be added in P3 (maybe by that that bosses drop nothing before P3?).
From other source i found, that they were removed from loot list in patch 1.6.0
About onyxia i did no boe, no pvp and only dungeon loot on paladin.