A few Q's about vnv

[GeneralMikeIII]

Hey, I was browsing through the Loc files and found all the different names and stuff for the vnv's, but I couldn't find any of the stuff that actually determines how a general gets one, and I came up with a few Q's I was hoping someone knew the answer to...

Firstly, does anyone know how to make it more likely for a general to get a vice or virtue?

Also, how are vnv determined? I know some are triggered (every time I order a general to "kill prisoners" in a battle, he gets "scant mercy", for example), but others seem random (like the "inbred" group of traits; some I haven't even seen in the game, only in the Loc files where they are defined!). Others seem like a mix of the two, like the steward virtues (in Territory A, I build all the Improved Farmlands and the governor gets nothing, but in Territory B I build up to Improved Farmland +40% and the governors is a "Great Steward").

Next, assuming there are three different classes like I guessed above, is there a way to change a random v-or-v to a triggered one (I don't usually keep my generals out of a battle, and they get tons of valour, but not once have I had a general get the "Great Leader" or "Great Warrior" trait unless it was a hero or a prince that was born with that trait, and if he was born with it they never go from GreatLeader1 to GreatLeader2, etc.).

Lastly (and leastly; I don't care about this one too much, but I figured since I was asking all these other Q's, I might as well ask this one too), is there a way to get rid of a trait (like if a general gets a "coward" trait, if you had that general lead from the front, thus getting the "Great Leader" trait, the coward one goes away. I don't think this is posible, since I have seen a general with "Moral Flexability", which decreases the bribery cost, and "Man of Principal", which increases the bribery cost).

EDIT: Post-Lastly (and even more leastly; this isn't even really so much a question as I think I know the answer), are there some traits that can ONLY be discovered by a spy? I think so, because some traits (like "Artistic Leanings" and "Family Favorites" and all those other friggen annoying ones that ruin what I have turned into a great governor otherwise) don't appear until late in the game, and the AI always waits to build agents until pretty late in the game.

...wow that was longer than I thought it would be. Oh well...