Starting City Quests

[Cleretic]

Palace of the Dead confirms that all three of them happen for sure, there's a dead NPC from all of them. Specifically, Gridania's is Janremi who stole a prized chocobo egg, Ul'Dah's is Garibold who tried to ransom Nanamo's crown for the Trader's Spurn, and Limsa's is Baenryss the Serpent Reaver. Not all of those NPCs died in parts of the story that the Scions were actually present for, so we can't say 'yeah Thancred did all that if you weren't in Ul'Dah'. But Enkidoh's probably hit it right that these were just done by other adventurers.

Remember that in ARR, there is absolutely dump-ass nothing saying that we're special. We've performed no unique feats up until beating Lahabrea, and in fact it's a fairly prominent part of the worldbuilding that we're just one in a crowd at the start. Hell, Edda's party is there to show you that adventuring is just a regular occupation full of people sticking their necks out for the coin despite the dangers (and also to tell you to not be an asshole to your healer, but many did not learn that lesson). Who's to say anyone special or interesting did the other starting questlines? Who's to say whoever did the others even survived for much longer afterwards?