RTF is a global modification that replaces all towns in the game.

2 Zobr
These are beastmen bred by mages. In the Fortress faction, they don't look that big, although they are quite large. Besides armor, they also use weapons. So, I think they are intelligent enough. As for why they aren't more widespread, it might be because they prefer snowy mountains. That's why I wrote that the model from the fifth game is most likely a snow gorilla, not a yeti.