Looking at the russian guide, here's what I found:
1) These units are Animals in KBAP: Fire Dragonfly, Lake Dragonfly, Werewolf (in wolf form), Unicorn, Black Unicorn, Hyena, Wolf, Bear, Ancient Bear, Polar Bear, Snake, Swamp Snake, Royal Snake, Griffin, Royal Griffin.
2) Humanoid is every male unit in this game with the exception of all undead units, ArchDemons and Shamans. These are affected by Charm and Beauty traits/abilities.
- On the side note, the persistence of mind trait should affect hypnosis and charming, but I'm not entirely sure.
3) The Undead are not affected by these spells: Bless, Resurrection, God Armor, Sacrifice, Weakness. Demons have immunity to the following spells: Healing, Plague, Hell breath, Necro Call and Light of Life.
4) Evlin can heal/resurrect undead units, and is an extremely overpowered spell, as it raises a % of the entire troop.
5) Archer are: Archers, Skeleton Archers, Elves, Hunters. In general, every unit that wields a bow and arrow.
6) Plants are: Thorn Warrior, Thorn Hunter, Royal Thorn, Ent, Ancient Ent. They have the persistence of mind trait (cannot be affected by mind spells) and cannot be affected by the following spells: Healing, Resurrection, Plague, Weakness, Necro call.
7) As for caution, lvl 1 doesn't have a def boost. The bonus starts at lvl 2.
Your question are very valid, because most of those abilities are considered "hidden" - meaning there is no clear explanation of them in-game.
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