The question then becomes what language to use for naming them. The circumstances that created the beastmen occurred at a time when the orcs had been brought to heel by the Tran and their human allies. The elves were also present on the surface, having been in conflict with the orcs and humans before the dwarves and their goblin army broke the surface. When the humans saw what the Tran did with the orcs, they realized that they were next; their technology was about the same level as the orc tribes, and humans of course lack any of the same physical advantages. Since Tinderbox is a godless campaign, the human tribes turned to primal spirits for aid. They received that aid, but the only spirits who answered the call were Primordial entities. I tend to treat Spirit/Primordial as more of a continuum based on the individual's view of living things in creation. Not unlike Banes versus spirits in Werewolf, only generally shying away from the more modern psychological/industrial identities found in that game.
These spirits offered power to the desperate humans, but they were only willing to empower them in exchange for a berth in the race's "souls" (which, in keeping with the non-divine nature of the setting, would really be spirits). The initial results of this were probably "liminal" monsters---thanks for teaching me yet another way to force that word into conversation, Wizards!---gnolls, minotaur-style ungulates, bearmen, etc. However, the offspring of those creatures, as well as any humans who either entered these compacts later or produced offspring alongside the original beastmen, more closely resemble shifters. When I say shifter I include longtooth, razorclaw, or anything else I decide to work up along those lines; Eberron had a great wealth of different, evocative shifter breeds which I do miss them in the current game. The variations amongst these breeds reflect environmental and cultural alterations, but all shifters are considerably weaker and less intelligent than the majority of full-fledged beastmen.
Adolescent beastmen are consecrated to the tribe's totem Primordial...which has considerable similarities to the genasi of the Silken Kingdoms. Of course, there's not been anyone with the opportunity to make this connection since the beastmen are insular and violent, and don't talk to other races. Most beastmen are going to embrace their tribe's spirit, but some will instead be traded away to a tribe their personality fits better. Beastmen who find no acceptance amongst their totems or who descend from tribes which never earned a significant totem's allegiance are the most likely to have something resembling a nonviolent relationship with other races---frankly, they don't have the power to do much else. I'm keeping the beastmen at a technological level that's far behind even the secondary races of the Tran. This means that members of the race who don't turn into awesome gnoll-dudes are in largely the same place that the original humans were, relative to the other civilizations on the continent.
But I'm attached to the rather bland "beastmen" name because it's so accurate to what, exactly, this race is. It also serves as a unifying term for both the undifferentiated (shifter) beastmen and the more uniquely identified tribes.
On the subject of tribes, later I'm going to fling up a few statblocks from the beastmen the parties in Tinderbox have faced so far. I built most of these beastmen using an online monster builder in late 2010, back when I was without Insider access. However, I ran every one of them through the official Monster Builder when I started the game back up. I'm still refining my touch when it comes to balancing monsters, as well as just building their slate of powers, so I imagine I may alter these core creatures as time goes on.