Short answers, pulled from the story.
Historical Vedic religion, also called Vedism or Brahmanism, was the religious tradition of some Indo-Aryan peoples of the Punjab and western Ganges plain during the Vedic period, roughly 1500-500 BCE. Its ideas and practices are recorded in the Vedic texts, and some Vedic rituals are still performed today. It is recognized as one of the major traditions that shaped modern Hinduism.
The Vedic religion has roots in the Indo-Iranian culture of the Sintashta culture, dated roughly 2200-1750 BCE, and the Andronovo culture, dated roughly 2000-1150 BCE, both located on the Eurasian Steppe. Before reaching India, Indo-Aryan tribes passed through the territory of the Bactria-Margiana culture (BMAC), borrowing at least 383 non-Indo-European words, including the names of the god Indra and the ritual drink soma.
Indra was the central deity of the developing Old Indic culture and the subject of 250 hymns, a quarter of the entire Rig Veda. He was associated more than any other deity with soma, a stimulant drink possibly derived from Ephedra. Many of his qualities were absorbed from the Indo-Iranian god of might and victory, Verethraghna, through contact with the BMAC culture.
The early layers of the Vedic religion did not include reincarnation or karma; they emphasized an afterlife and ancestor worship through rites like the Sraddha. Ideas about reincarnation and karma began to appear in late Vedic texts, including the Brihadaranyaka Upanishad dated to around 800 BCE, predating the Buddha and Mahavira.
Brahmanism developed out of Vedic religion in the late Vedic period, taking shape around the Ganges basin around 1000 BCE. Unlike Vedism, Brahmanism incorporated post-Vedic texts like the Dharmasutras, placed commanding emphasis on the priestly Brahmin caste, and added non-Vedic religious ideas including early karma and reincarnation doctrines from the Upanishads. The word Brahmanism was coined by Goncalo Fernandes Trancoso, who lived from 1520 to 1596.
Yes. The Nambudiri Brahmins continue the ancient Shrauta rituals, and complex Vedic rituals of Shrauta are practiced in Kerala and coastal Andhra. The Kalash people of northwest Pakistan also continue a form of ancient Vedic practice. Michael Witzel has also proposed that Shinto, the native religion of Japan, contains some influences from the ancient Vedic religion.