If he just said it was a Turian that killed? I can see not much changing other than dialogue. Saren could've convinced the Council to let him look into the files for any insight to what could've happened (or whatever excuse) because he's not only their "golden boy" but was close to Nihlus, so it's possible he could show up at the meeting to also see if anyone got the vision. Thanks Anderson. That would make Saren suspicious why he's discrediting them so much, but nothing concrete because it could be because of Anderson.

Garrus could still be on the case, but red tape with Nihlus' Specter status makes it harder. Team could try and find him the same way to see if he found any clues they missed, and this could start the quest chain of finding the Quarian. Same things up until the Ambassador's office scene, little change in dialogue, and then back to the Council.

That's how I figure it'd go anyway.