Yep, as cool as all those theories are, it's quite simply Gary Vader, a real human being from Lucas' youth, not "INvader," or Dark Father, etc. Even the "Son of the Suns" and Hebrew words on Vader's chest plate turn out not to be all that on further examination. But we fans like to follow those rabbit trails, don't we?
Those are simply happy coincidences after the fact. I bet if Lucas had used one of the other randomly generated names for the character, we'd likely be sitting here repeating alternate lore about its significance and foretelling of future events in the saga.
It's just that "mythical quality" given to the franchise (for better or for worse) and massive popularity that fuels such things.