CAppearanceModifierDef - Decides things like:

Appearance type (which I think is an unknown in FE)
Clipping Prevention (Used for clothing and such. And when making a new clothing mesh)
Appearance Clothing Model (Appearance? Hair. I think. I'm unsure.)
Removable (Whether the item is removable or not - ie Jacks mask isn't removable)
Hero Suit (Whether it's a part of a suit or not e.g. Bright Plate)
Suit Part (Self expanatory - head, legs, chest etc)
Appearance type (another unknown in fable explorer - I assume it decides whether you look good or evil - something like that)
Scariness (Self explanatory)
Attractiveness (Self explanaotry)
Alighnment Modifer (Good, Neutral and Evil)
SoundRadiusMultiplier (This would probably decide how loud you are in game. ie cloths are light therefore quiet while plate is loud)
VisibilityMultiplier (How easy you are to see in game - ie the assassin set is harder to see the bright armour sset)
ArmourDefIndex (How much armour I assume)
ArmourPercentage (Float value I think, never used it though.)


CAnimatingObjectDef

Animation (Self expanatory)
Action (what an item does in game)
Several unknowns in this area


CAreaOfEffectAttackDef

TrapIndex (Think of the rock troll jump thing)
ExplosionIndex (I assume decides whether there's an explosion or not)
ObstructionRadius (Another unknown float value, but I assume it does what it says.)
ObstructionLifeTime (Another unknown float value, but like above I assume it does what it says)


CAugmentationDef

Name (e.g. Silver Augument or whatever)
Type (uint type - no idea)
InventoryGraphic (the texture in the menu - the silver ball type thing for the silver agument and so on)
DamageMultiplier (multiples weapon damage [Weapon damage * value (squared)])
Healt hRegeneration Rate (the rate in which health is gained, I would assume - float value)
Health Update (number of seconds to update health bar)
Mana Regeneration Rate (See Health Regeneration Rate)
Mana Update (See Health Update)


CBalverineBattleDef

four unknowns

CBettingDef

Bet (links to a textid text gui betting bet)
PlayersMoney (gui of money draining/gaining i assume)
Question (this seems to link to TEXT_GUI_BETTING_QUESTION which says 'Temple of Avo, please give generously.' a fable joke?)
Rest are unknowns (total 9)


CBonusItemDef

HealthModifier (Add/decrease health)
AddsFatness (if yes how much if no then 0)
StaminaModifier (seems to be will...)
SecondsHealthGiven (how fast health is given)
WillExperience
SkillExperience
StrengthExperience (add/decrease/none [includes above 2])
MoralityChange (good, evil. ie crunchy chicken and tofu)
AgreeablenessChange (changes difference between villager following or not higher = follow lower = refuse)
AttractivenessChange (how attractive you are - admiration)
ScarinessChange (run or not - crap themselves)
MaxHealthIncrease (ie elixir of health increases your total health permanently)
MaxStaminaIncrease (related to mana - elixir of will property - see above)
AttackSpeedIncreaseTime (if it increases attack speed or not - there was a potion that had an effect on this - was removed)
ParticleEffect (used on potions/elixirs i think)
AddsDrunkenness (ie beer makes you drunk but tofu does not probably boolean ie true or false)
AlcoholicStrength (determines how drunk you can get off a substance i believe... or how fast)


CBuyableHouseDef

IsBuyable (byte - 1 or 0 - able to buy or not)
Initially empty (e.g. oakvale home was empty till hero buys or buy & rents it - true or false (in bytes))
Price (determines price of homes - unknown)
IsScripted (unknown to me)
3 more unknowns in here


CCameraCollisionDef

CameraCollisionMesh (decides where the camera will be I think. Boasting podium could be a good example)


CCarriedReadableDef

TitleTextTag (title in menu)
BodyTextTag (description in menu)
I doubt these are even used


CChestDef

OpenParticleEffect (Animation opening? I don't know)
ObjectNeeded (what type of item is needed e.g. silver keys)
NumberNeeded (how many of ObjectNeeded is needed - 10 silver keys for example)


CDoofDef

TriggerType (Hero does something - Villager closes door. No idea.)
TriggerRadius (How close does the npc have to be to close the door)
OpenCollisionMesh (ie bowerstone door - if you're close enough it opens - this is its 'open mesh)
ClosedCollisionMesh (ie bowerstone door - if you aren't close enough it's closed.)
3 unknowns

Not 100% as to whether all explanations are 100% correct, but I'm only human.