Also problematic is that he attacks Eden Prime for a Prothean beacon. Why does he need that one when he has a Prothean beacon on Virmire?
Considering how rare Prothean artifacts, especially functioning beacons, seem to be, he likely did not have one at the time. I believe he only acquired (another) one after the raid on Eden Prime.
Near the start of ME1, when Shepard first tells the council that Saren is up to no good, they dismiss the accusations straight away. Yet when he comes back with some random Quarian (who owes Shepard their life) and an audio recording of someone with a voice like Saren, the Council instantly accept the same accusations without any further investigation. Even today it's possible to fake a recording, either by using soundalikes or by careful editing of source material, so might it not be even more easy in the future?
That's the council/Sparatus.
Guy mentioning Saren, who has never seen or heard of him before: Untrustworthy
Tali's easily fakeable recording: "Irrefutable evidence"
Giant Reaper ship, seen by multiple cruiser crews and station inhabitants, evidently not made by any known galactic civilisation: "We have dismissed that claim"
Anderson probably should have mentioned that the info about Saren came from a reliable fortune cookie -Sparatus couldn't have said anything against that!