great idea no doubt fantastic even but I think that for a proposed origin story it would for the Quarians you need to start farther back than the flotilla maybe on the Quarian homeworld before during or right after the battle against thier creations the Geth. And probably the same for some of the other races as well. The Humans for example would ideally start at during blitz or at a time when primitive lead firing weapons were their primary arms just before more advance tech was adapted and the norm