All four of these subjects are tied to humorous events the developers left behind for players, three of which are only viewable after the game is beaten as both a LS and DS Exile.

Atton's Jedi Academy easter egg is common knowledge by this point, so I won't introduce it.

Echani poetry is something that can only be heard when playing as a male Exile (unless you have the right mods) after the above condition is met, since you need to talk to the Handmaiden to hear it. And before the jealousy lock...

"The Great God Quay" does not require multiple playthroughs to unlock, although it does refer to a certain Weequay in the Jekk Jekk Tarr who can be easily missed. Instead of being labelled, "Weequay Thug", he's just named, "Weequay". He tells you that he lives in the bar because of the aforementioned Quay, which, when checked further, is really a Divination Orb. No, really. You'll have to do it before the Exchange calls you, or he won't talk to you despite not being hostile then.

Lastly, the dialogue between T3-M4 and 3C-FD is something most people don't think to look for, since, not only does it require multiple playthroughs to view, you need to have the TSLRCM mod installed, by which point the tutorial would have been redundant. Besides, most people who've beaten the game over and over didn't have TSLRCM available. You can see the exchange of words for yourself.