What other deities and entities are associated with this deity?
To answer this question with, “All of them” would be easy and not wholly incorrect. Antinous has the gift of making connections among gods and between gods and mortals. He is often described as a “gateway god”, someone who attracts people to polytheism by their worship of him.
However, a facile answer doesn’t make for a very interesting read. Therefore, I’ll offer my opinion on the deities and entities that are definitely associated with Antinous.
First and foremost, of course, there is Hadrian. Without Hadrian’s relationship to Antinous, we would likely know nothing of the Greek youth from Bithynia, even if he had travelled to Egypt and drowned in the Nile under other circumstances. Antinous still would have been deified, but his cult would have been confined to a small locale instead of promoted around the Empire. Without Hadrian, we would have no statues to immortalize Antinous’ beauty, and one less model of an erotic, even romantic relationship that in some ways broke the rules for such relationships by its intensity.
Along with Hadrian I must mention his wife, Sabina. That may seem strange to our sensibilities, if we are thinking of Sabina as the wronged wife of a man having an affair with a younger man. A few considerations have helped me to understand Sabina’s importance. First, that categories like heterosexual and homosexual really do not apply in the ancient world; in both Greek and Roman culture, adult men could take whatever partners they wished, male, female, slave, free, as long as they were appropriately dominant. The double standard wasn’t a hypocrisy, it was simply a fact; men were not under the same sexual constraints as women.
Second, that it would have been simple for Hadrian, once established as Emperor, to divorce Sabina and replace her with another wife, or no wife. He did not. And third, he ordered her divinization, which along with their continued marriage leads me to believe that he had affection and respect for her and found value in their partnership. The Obelisk of Antinous portrays the divinized youth praying for Hadrian and Sabina together as rulers of Egypt and the Empire; I think his worshippers should do no less than honor them together in the same way.
After Hadrian and Sabina, Antinous’ closest connections are with the four deities with whom he was most often syncretized: Osiris, Dionysus, Hermes, and Apollo. He became Osirantinous upon his death in the sacred river. The Greeks had already syncretized or equated Dionysus with Osiris, and much of Antinous’s iconography borrows from the traditional depictions of Dionysus. Antinous was syncretized with Hermes as a messenger, communicator, interpreter among the gods, and with Apollo as an oracle, healer, and inspirer. With the exception of Osiris, these gods are all portrayed as youths, the children of Zeus rather than the first generation of Olympians.
Besides Sabina, the goddesses with whom Antinous has the closest connection are Diana, especially at Lanuvium, where a burial society was dedicated to both of them, and Juno, who was also worshipped at Lanuvium. I find it interesting that both of these goddesses support female sovereignty, Diana the virgin huntress, refusing the ties of marriage, and Juno the queen of heaven who gave her name to the divine spirit within every woman.
Those are my choices for the deities most closely associated with Antinous. But I still stand by my original answer: The deities connected to Antinous? All of them.