It took me 130h in Mass Effect 1 to find out that on the Mako I can activate zoom view with the left shift key :-p
And yesterday I used the Gibbed-Savegame-Editor for the first time and took a look at the plot-flags - there is mentioned an NPC I never met 'til now although I have two chars who come from earth: Finch. He seems to be at or near Chora's Den, but I never stumbled upon him 
Oh, and somewhere else I read something about Liaras father and a related quest? Never heard of him/her, and this is my third playthrough now 
Well, there seems to be plenty of stuff left to discover 
Yah, the Shepard Origin Sidequest... Finch appears only if you choose an Earthborn Shepard. But this encounter is only triggered on the time you visit the Citadel after completing one of the Main Missions first (Save Liara, Feros or Noveria)
*As is the arguing couple (Rebekah and Michael), Planting a Bug for Wong(Only available if completed the first mission for her), interview with Al-Jilani and the Normandy inspection.
On a side note, in ME2, you can check the flags for the three Origin-related Assignments and you'll recieve an E-mail from Finch, Talitha(Colonist) and Shep's Mom (Spacer),as if you completed them all.
(Of course, I just tested this in ME2, but IDK if you still get a call from your mom in ME3: Citadel DLC if you're an Earthborn or a Colonist, even if those Plot Marks are checked)
And Liara's "father" only appears if you talked to Liara in the Presidium Commons, then returning to that area(Taking an elevator to another floor then come back or simply Quick Save/Load) before completing Priority: Tuchanka.
Convincing Liara to talk to her gives you a few War Assets for the Asari Fleet, but no Sidequest... I think that the sidequest you're refering to is to actually meet Barla Von on Liara's behalf. Then, he gives you a mission.
Fun fact, cut Citadel News in ME2 said that the Shadow Broker had been cleaning house and that Barla Von was found dead... But then, it's cut. There is a vid in youtube if anyone wants to check it out.