(all unrelated post on this thread will be deleted)
Ok, I may not have been clear enough will all thoses NPCs things so here are some explanations:
NPCs are there to further quests, and as such they have knowledge or power that PCs cannot posses. Most of the time they know things that PCs don't or "roplay control" area that would be impossible for PC to control. Take the example of Franco, as the mayor he has control over all civic buildings and have his word to say on all commerces in Vesper, you cannot go see him and disrespect him 'cause he will have you jailed... for a long time...
As another example, a criminal overlord would control a hell lot of underlings (hit mans, crooked gards, dealers and the like) but thoses cannot be seen ingame since there are a maximum number of AI controled NPC that can be in the same area at the same time (too much means crashing the server, and we sure don't want this to happened) so thoses type of NPCs have dynamic stats, they are stronger when in the are they control and weeker outside of it (all of this to simulate their relative power).
So, before interacting with a NPC ask yourself this: " If he was the [insert NPC tile] of New-york, as a person how would I interact with him?"
This bring me to combat NPC, and in particular all powerfull NPCs (like Sobran or Parya) I try to play them as fairly as possible, I attack at random (usualy closest) and cast offencive spells as I see fit (I have no casting dealy but I try to "simulate" it... that is unless the situation demans otherwise) but I try only to harm my opponent before going to the next and I will kill only the worst offenders (thoses who spam heal when I have finished with them and come at me charging back). So if you come in combat with a NPC and its not a fight to death ('casue NPC consider death to be permanent) and you are criticaly harmed then run or you may not have the luxuary to loot your corpse back. I also know that most spells dont work on me when I control NPCs (necro spells for example) but I try to Roleplay them as I can. You have to understand that fighting with an NPC is far from obvious since its really different from fighting with a PC but I'm doing my best to be fair.
Also, I cannot control efficiently more then one NPC at the time, and I cannot switch from one to another fast enough to my liking. This means that you can get erratic behavious of your character if you try to disregard something that a non-gm-controled-npc said (from having your char moved, stoned or killed).
And please, for the love of god, stop saying "train", "teach", "buy" and "sell" to my NPCs, it is very insulting. Usualy they have a unique item (Franco got a Mayor sach and cloack for example, Parya got a pure black stang) but, what should really give it away, is that they Role play
But the most important thing is still to Role Play in front of NPCs, don't bring your horses inside houses, dont have weapon drawn, dont use too much "lol" and "brb". If you really have something to say out of game in front of a NPC use parenthesis ( ) or use AIM. And remember that all quests are dynamic, your actions will change the quest, and your reactions could close you doors, or open some new ones. Nothing is hard scripted, everything is subject to change. Be creative, think of what you'd do in this situation if this was real life (in a medieval setting

) and ask around with both NPCs and PCs; every quest are made for guilds, so some guilds may have clues for you (and if you have clues for another guild, you should sell them, not give them away).
So that is pretty much it, if you have any questions, if I was not clear on certain points, feel free to ask here. Someone in every Reguistered Guild should have my AIM if your question cannot be asked on a public forum.
Remember that I do this so you guys have fun... and that it takes more then 40 hours of work per quest (and I have 3 running as we speaks)