confused about lines in Finding Nemo

The conscience thing is riffing on a trope where a character hears their conscience as a physical voice telling them right from wrong. It can be traced back to Pinocchio, with Jiminy Cricket acting as Pinocchio's conscience. I think in this case, Dory is hearing Marlin's voice and thinking that she's hearing something supernatural when she actually isn't. 

In the "did your man deliver?" scene, Marlin is using the definition of deliver that means "come through with intended results." He's talking playfully to Coral, in a way where he pats himself on the back for doing such a good job at picking out a house for them.  There's also an additional connotation here: there's a certain informal and humorous English phrasing where people will say the same word twice but emphasize it the second time. Say, for example, someone was discussing spicy food. They might say "was it spicy, or was it *spicy?*" The first mention of spicy would be referring to an average amount of spice, while the second mention would refer to food that is genuinely spicy. So, Marlin is joking around with his wife by basically saying, "did I kind of deliver, or did I REALLY TRULY deliver?"

1. Marlin delivered - fulfilled - his promise to show Coral something amazing. You can deliver a letter. You can also deliver a promise. 2. Conscience, in this part, means her inner voice. Her own thoughts. She's asking if the voice she is hearing is inside her own head. Marlin plays along, and says yes, it's her inner voice speaking.