She was called'Sri'. She is mentioned in the Rig Veda,the oldest literature of the world. This is the Saubhagyalakshmi Upanishad. Though we have the Sri Suktham,Saubhagyalakshmi Upanishad directly imparts Yoga.
We have, thus, Shaiva,Shakta,Vaishnava Yoga Upanishads. And we have Samanya, common Yoga Upanishads for Gruhastha or householders and Sannyasa Yoga Upanishads for the Renounced. I have written on some of these Yoga Upanishads. Shall write further.
It has nothing to do with the belief in God. One can be a Hindu and remain an Atheist ,like Carvakas, Buddhist,Ajivaka. These are totally opposed to Vedas and deny their authority. Orthodox systems are those which belive in the Authoroty of the Vedas. Those, like Jainism are called Heterodox and they do not believe in the Vedas. Even among the Orthodox systems which believe in the authority of the Vedas deny God, like The Nyaya System.
It is called Urthvarethas, Meaning that the semen flows upwards through the Chakras in the body to reach the Sahasrara in the head, This Celibacy is called Naishtika Brahmacharrya.(not allowing the semen to flow down) Bhishma is a Naishtika Brahmachari. He is the only Naishtika Brahmachari, apart from Hanuman. This is the reason, why Devavrataha, was called Bhishma, one who does the Impossible. In the case of the Grahasthas, so long as their object of physical interaction is to produce progeny without Lust, they are also rated high in the scheme of things. King Janaka is one such.
Though the body ceases to exist, the remnants of actions performed, Desired do not cease even after death. The thoughts remain as energy once created can not be destroyed and Thoughts and Thought processes are Energy. They have to be expended. Till such time the Subtle body remains. The Subtle Body is called as Sukshma Sareera.