Melee attack rolls are melee attack rolls, whether they're backed by the base attack bonus of Roy or Vaarsuvius or any of their peers, too; that doesn't mean Vaarsuvius' performance with a melee attack roll is equivalent to Roy's performance with a melee attack roll.
I think there's another point there you're missing: you seem to be assuming that the existence of a convoluted way for a prophecy to be construed to pass means an obvious way for a prophecy to pass is off the table.
If Durkon were to die, come back as/in a vampire, return to his "beloved dwarven homelands", be destroyed, come back as himself via resurrection, die, and be buried in his ancestral tomb....Events after which instance of death could fulfill the prophecy? Both, right? The existence of the more convoluted answer ("posthumous" as in "after dying") doesn't negate the more straightforward answer ("posthumous" as in "while dead").
If Roy were to be told that Xykon would be within 1000 feet of Girard's Gate, prior to/instead of being within 1000 feet of Kraagor's Gate, then Xykon came with range of Soon's Gate, then much later Xykon were to arrive within 1000 feet Girard's Gate without any time to interact with the Gate....Was the prophecy given to Roy fulfilled? Yes, right? That the prophecy Roy got was more restrictive than the question Roy genuinely thought he was asking didn't render the prophecy invalid.
So, if Belkar lost the ability to breathe without dying before the end of the year, and then died before the end of the year...wouldn't the prophecy still have been fulfilled? And if so, doesn't that mean any and all theorizing over whether/how Belkar's prophecy has been fulfilled is tenuous until the end of the year, without needing the prophecy to be inaccurate or convoluted?