Brahmanism was the religion of aryans, and was the primary form of Hinduism. Brahmanism was influenced by many other and accepted the best parts from them, thus Brahmanism was transformed into Hinduism.

He was opposed to caste system in Brahmanism.

No. Brahmanism came from Hinduism.

Both Hinduism AND Brahmanism are almost same. Hinduism is said to be found from Brahmanism.

Brahmanism is a religion that was founded in ancient India. Before Brahmanism there was Vedism. The class of priests were called Brahmas.