The girl that murdered Ganoes Paran is named Sorry, as you know. She was possessed by Cotillion, the Assassin of High House Shadow. High House Shadow is like a faction in the Deck of Dragons. Think of the Deck as a card game with different factions, each with unique roles. There are kings, queens, knights, assassin's, hounds, champions, heralds, soldiers, the list goes on. This Deck has an impact on the 'real world' and the roles in the different factions are played by 'real' people. I'm not going to tell you how the Deck exactly works. Partly because I don't completely remember it and partly because most of it will become clear as the story progresses.
The other people mentioned in your posts are Hood, indeed the 'god' of Death (or ascendant, godhood works differently in Erikson's world, you'll find out in time), who is also King of High House Death, the Twins of Chance (or a single entity named Oponn) and a certain servant of Hood, who is probably just that. The other guy in that particular scene is the King of High House Shadow, Ammanas, or Shadowthrone, who ordered the murder of Ganoes Paran. Paran got sent back (in Erikson's world, things like this are possible) and is very much alive, body and mind.
To wrap it up, Shadowthrone, Cotillion, Hood and Oponn are indeed all ascendants, or gods, who have managed to get themselves a place in the Deck of Dragons. Paran got stabbed and was held back before Hood's Gate (the doors to the underworld, if you will) by the Twins of Chance, who then tried to bargain with Hood. Shadowthrone came in with his hounds to finish the job (and drove the Twins away), but Paran convinced Shadowthrone to spare him. As he did not bargain with Oponn, I presume he thinks that no one will die in his place, but I'm not sure honestly if someone did.