"A hero destined to brandish what the Earth hath swallowed" = Brian, the chosen Captain Britain of almost every reality, the last time we saw the Sword of Might it was being hidden underground.
"Echo doomed to yearn for what the stars hath forsworn" = Betsy as replacement Captain, possible reference to the Starlight Sword.
Something to keep in mind, this prophecy was framed by Saturnyne, and she has made her preference for Brian well known.