Has anyone claimed to have reborn in Pure Land, and later returned to earth to help other beings?
Usually the Bodhisattvas who vows to be born back to Earth to guild others will do so with the means appropriate to the culture, time and age.  In this age of Dharma descend, they would not display enlightenment or supernatural powers, but instead would display mindfulness of Amitabha Buddha and recitation of His name.  They would show signs that they obtain rebirth to Pureland.  And they will never reveal their true identity.  Master Chin King often said if the Buddha or Bodhisattva identity is revealed they would immediately depart from this world.
Namo Amita Buddha.