After more hunter research i found that a pet from the same family tree will have different stats.
Two carrion birds (one from Westfall and one from Redridge) had different armor. The level 16 from Westfall had 100 more armor than the level 18(!) from Redbridge. And this is without any training.
Again, pets are not normalized - just attack speed...? This makes no sense at all. Every carrion bird, wolf or cat should be identical to every other carrion bird, wolf or cat (in dps, hp and armor). So why do they differ?