Short answers, pulled from the story.
The literal translation of Nirvana is blown out or extinguished. The Sanskrit verbal root meaning blow combines with a preverb meaning out and a past participle form to create the term nirvāna.
Buddhists seem to have been the first to call this state Nirvana according to Collins. Vedic texts like the Brihadaranyaka Upanishad discuss spiritual liberation concepts before Buddhism emerged but do not mention soteriological terms like Nirvana directly.
Buddhism contradicts the Atman doctrine by claiming no permanent self exists through its anatman teaching. Hindu texts describe Nirvana as stilling mind but not inaction while viewing it as infiniteness rather than emptiness.
A Kalpasutra folio depicts Mahavira Nirvana showing a crescent shaped Siddhashila where all siddhas reside after liberation. Uttaradhyana Sutra provides an account of Sudharman explaining meaning to Kesi a disciple of Parshva.
Nirvana appears in Sikh texts as the term Nirban though Mukti or Moksh remains more common. Sikhs treat liberation not as an afterlife concept but as a goal for living people through loving devotion to God.