There are items belonging to the clan: Bonechewer Spear, Bonechewer Remnants, found in Gul'rok which in the main universe is the location of their village which seemingly confirm their existence in the alternate universe.
The Bonechewer clan is the only named clan to not be mentioned as a part of the Mag'har clans. This may be because of the clan's heavy affiliation with the Shadow Council or that they were wiped out during the events of Warlords of Draenor.
This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
Given the presence of Tagar in the ranks of the Shadow Council and Gul'rok being controlled by the warlocks, it is possible that the Bonechewers are the nameless members of the Shadow Council. Lo'marg Jawcrusher and Vorpil Ribcleaver, a pair of Shadow Council members in Telmor, not far from Gul'rok, both have a name structure similar to that of Hurkan and Tagar and use armor and weaponry matching the description of Bonechewer orcs wearing the bones and organs of fallen enemies. Furthermore, upon dying Vorpil exlaims that Teron'gor said... we would have the bodies... and he would eat the souls..., implying cannibalism. The fact that Hurkan Skullsplinter was also a member of the Shadow Council during the Warlords of Draenor beta can only confirm furthermore the speculation.