True, but Apollo was not God, he was just one of many gods, and not even the highest.
The Apollonian ideal was countered by ideals associated with other gods, notably Dionysus, whose motto was (paraphrased), "Anything worth doing is worth overdoing."
Ancient paganism was not a religion, it was a whole group of religions. The devotee could seek out the one that best suited him. The closest to this in the modern world is Hinduism.
Yes, the article made it clear on polytheism - many gods, many goods and many moralities. He did only mention three - Zeus, Apollo and Neptune but it would take a book to mention all of them. His point was that moral relativism is the equivalent of the old polytheism where each become a god or goddess, a giver of law rather than a receiver.
Quite correct, Hinduism has forms ranging from atheism to polytheism to monotheism.
By that strictly accurate definition:
Hinduism is the pagan faith of India. Shintoism is the pagan faith of Japan. Animism is the pagan faith of Africa. Druidism for Celtic Europe, and Wotanism for Germanic Europe.
Now obviously there's a fair amount of variation in that little lot! However there are similarities. They are polytheistic, and essentially forms of spirit and/or nature worship.