One of the Dark Brotherhood side quests involves a contract on one of the Khajiit in Risaads caravan. Well in the process of killing him,two others Atabah and Khayla died. I know the Dead Thrall spell can revive a character permanently, my question is, would reviving those two bring them back to their prior routines? Ie they would pop up with Risaad and I could do business with Atabah, and Khayla would resume being a guard?

Dead Thrall spell does not revive anybody, it merely animates their corpse as a mindless slave. So, no, they are permanently dead, and I wouldn't be surprised if Ri'saad will consider you an enemy. That's the price you pay for being a member of the Dark Brotherhood: you will make a lot of enemies.

risaad still does business with me despite the assassination of the khajiit in his caravan. I read that some thralls resume their previous routines, and you see thralls from vampires going about routines without being slaves.

No. Thralls are bound to your will. They're slaves, nothing more.

And no, you can't command them to go about the routines they had when they were alive.

Thanks for the reply Korthurn. And i had thought previously that Khajiit traders were not killable.

are you on PC or console?

if PC, use the command "resurrect" on their corpse

"resurrect 1" so you don't bring back a copy but the original dead npc.

also I snipe the khajiit from a distance with a bow so no one notices me. I'd hate to kill the khajiit.

I'm on the ps3 console sadly. And i dont want to have to restart my character just because of a mistake of bringing my follower Kharjo with me.

In the first two worlds game there was a spell that revives people and they would go back to doing what they where doing.

Another reason not to join the Dark Brotherhood... as if killing innocent people, communing with a frickin' corpse, and getting the most interesting characters in the game killed isn't enough.