At a quick first glance, everything looks good for the three characters. I'll go over it more this weekend.
Tailspinner aka Andus
Andus looks good. That CHA hurts!
Looking at the background, since you are a "native" of Ravenloft, you will be more aware of the world limitations. Kalidnay is the only "city" reachable to your best experience but there are a number of large towns in the desert. It was one of these you traveled to.
As a gladiator and since you mentioned you tended to play with your foes a bit before finishing them off, you may have earned some Ravenloft traits. These act as bonuses under some circumstances and negatives in others. Basically you understand you may have been cruel for no true reason that to entertain others.
Let me know and I'll look up the exact details. It would lend to role playing oppertunities.
Argent aka Socrates
Socrates look good. With magical quarterstaffs I consider it magical throughout the weapon, not just a specific tip. So +1 to each strike if you strike using both ends. I'll look up the Dragonfly. I have it somewhere. I'll need to think about it's benefits to you as it's "master".
What I have decided is the City has hired you to repair it's sewers and underground water systems. They have never been worked on / repaired since the original construction of the city. You were hired both for your knowledge and for the obviously combat based friends you have on retainer.
After you agreed to the contract, you learned that many recent expeditions into the sewers by past repairmen has lead to their never returning again. There are rumors of Tari (rat-like humaniods) running rampant there along with something....dangerous. Something rumored to be reptilian and a killer (Thus a tie-in to current storyline already underway).
Velmont aka Adament
Looks good. I am curious about one thing....are you a native or are you a cross-over like Jayde, Odten and Tallask? You said in your background that your slave brands/tattoos are gone. How? If you wish, I could have it that you know something is wrong here also, that King Tenk is no King. Just a thought. Let me know.
I have officially introduced the three of you into the group. You were searching for the sewer entrance (Tallask just came out of it about ten minutes prior and explains why you are within the rose feilds yourselves).
Welcome. Welcome to a darker Darksun......