1) does the smoldering corpse bar exist outside of planescape torment. and if it does, is it still called the smoldering corpse bar in a post-torment sigil?
I actually don't know. I don't *think* it exists outside of Torment (which isn't canon though it is a Wonderfully PS style story, the plot just doesn't fit to the canon plot).
2) what does the river styx taste like?
No one would ever remember to tell you.
3) besides Nordom, whats a good name for a rouge modron?
See the Cog Squad game in the RPG forum for examples.
4) is there a war of guilds in sigil, as well as factions? and if so, how do these guilds react to competetion? (ex: would a planeswalker's guild give an independant planewalker for hire some 'advice'?
Yes. Though it's not a war of beliefs as a war of economies. The guilds in Sigil (post Faction War especially) have attained power and would like to retain it. There are a few rivalries between groups (Kylie's touts and Autochon's Messengers I think) but generally with the guilds it reflects more a matter of economy and territory - not philosophy. If you're familar with inter guild quarrels from other settings the same applies here. In the case of a planewalker's guild, they'd probably try to recruit him. Not all the guilds are going to go in willing to break knees to get done what they want done, it's not good for their reputation or their business. (Now, arranging for a law to be passed that fines unliscenced planar guides... that's something else entirely.) 
But it's in the Clerks ward not the hive... wandering corpse works too.
