I see. It's a shame since the AI variables documentation is just great
The AI was completely rewritten from scratch for DOS2, and the person who did that was fortunately very diligent in documenting all of those knobs.
Also, ArmorRegenPercentageGrowth and its MagicArmor counterpart, what do these values mean?
When a character is not in combat, is not dead, does not have an incapacitated status, and does not have the
NO_ARMOR_REGEN tag, then every frame the character will recover "ArmorRegenConstGrowth + ArgemorRegenPercentageGrowth * 100.0/maxArmor" physical armor points. It's similar for magical armor.
And this one: SkillAbilityDamageToPhysicalArmorPerPoint?
This is the damage bonus to physical armour that you get per point invested in the "Warrior Lore" ability, which I think corresponds to "Warfare". The bonus is calculated by interpreting SkillAbilityDamageToPhysicalArmorPerPoint as a percentage, and multiplying that by the number of points invested and the damage done to physical armour by an attack.
Also, I've found mentions of a bunch of talents that you can't find in-game. Some of them even have requirements, like WarriorLoreNaturalArmor or RogueLoreHoldResistance. Is there any way to enable them using mods?
Those talents are mostly leftovers from DOS1. You can add/remove them with the CharacterAddTalent/CharacterRemoveTalent Osiris calls (or possibly grant them using the properties of a custom item).
Code generally won't do anything when someone gets this talent, but you can react to them being unlocked using the CharacterUnlockedTalent Osiris event and do whatever you want. This allows you to add custom-behaving talents to your mod, even if you can't choose the name. In case you did not know, there's a list of all valid talent names and in many cases also what they do (if anything)
on the wiki.