I've just killed all the slavers after they turned up at the Temple of the Union. Now it says says talk to Hannibal, but he just keeps saying "what can I do for you?"

I got the picture of the Lincolin Memorial, but can't find Caleb Smith anywhere to give it to him?

I've looked everywhere for his body but I can't find it, so he didn't die. He just vanished. There are just 2 people left at the Temple of the Union, Hannibal and Bill Seward. They just hang out in the Temple and won't go to the Lincolin Memorial.

Any help would be much apprcieted guys.

I'm going to guess that you're playing on PS3, this is a known bug for that console (though I suppose it could still crop up for others).

To get the slaves moving, attack one (preferably without killing him), turning the slaves hostile, then run away. Once you get far enough away to fast travel go somewhere safe and wait for 24 hours. Now go to the Mall NW Metro Station, wait another 24 hours, and like magic they should appear and not be hostile. If they are still hostile then reload and try waiting longer before you you go back to the metro station.