[Matrixbeast]

Bulk, Phenomenus (However that's spelt...) and Karone were all carried over.
But Leo directly states that he was there when the Space Rangers saved Earth, further helping the story link.

Also, Bulk's been back on Earth since at least Wild Force. It's not explained how he got back from Miranoi, but with all the teleportation technology about (Maybe an Aquatian lent a hand?) and all that wormhole business, it's easy to come up with a quick explanation (Especially considering how quickly the Galaxy Rangers manage to traverse to Earth and back).