I'd hesitate to categorically lump all of the ancient mystery religions in with the rest of your list. Some of them were pretty strange, even for the ancient world, but e.g. the Eleusinian Mysteries and Mithraism were very mainstream for hundreds of years.
Mithraism, in particular, is arguably very tightly linked to Christianity in early Christian history. By one theory, before Constantine's reforms that merged the two religions, Christianity was popular among the plebians while Mithraism was very popular among the patrician class, and the modern form of Christianity is arguably more similar to the old religion of the patricians.
I'd hesitate to categorically lump all of the ancient mystery religions in with the rest of your list. Some of them were pretty strange, even for the ancient world, but e.g. the Eleusinian Mysteries and Mithraism were very mainstream for hundreds of years.