so I have blown up all the warheads, found all the posters of Ralphie, and found the 10 nostalgia notes.

but I only got four of the six things with the courier's past.

I am pretty sure they are all triggered by dialogue, but somehow I missed two.

anyone get all 6?

Yeah you got expend all Ulysses dialouge trees. I got 'em all in one conversation.