LucasArts has stated that the Light side male story is canonical.
Ebon Hawk: Oh, right, sorry. I haven't played the game through as Light side, where this Ebon Hawk end movie appears. Playing as Dark side, you see a video where the Ebon Hawk is crushed by boulders before falling into the abyss. Since the Light side is canonical, the Ebon Hawk does survive.
Revan: If he became the Dark Lord out of necessity it means that he never fell to the Dark side, his plan was always to save the galaxy. Thus no fall took place, he just became a character that would be needed to save it. If his intentions were good all along, he never was Dark side. He could do the same again, but since he has clear, good motives, a "fall" would just mean assuming a new role where he betrays the Sith, as was his plan all along.
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Good intentions mean nothing. Ulic Quel'Droma fell to the dark side because he was trying to defeat the Krath, who had killed off the rulers of the Empress Teta system and were attempting to build a new empire from the Sith teachings, killing several Jedi in the process. Luke fell to the dark side because he was trying to rid the galaxy of the Emperor's clones and bring freedom to the galaxy. If Leia hadn't intervened he wouldn't have been able to come back to the light and likely would have ruled in the Emperor's place. Falling to the dark side to achieve a good goal is still falling to the dark side.