I would say your second conclusion sounds closer to the mark. All the pagan mythologies that contain echoes of the gospel are what C. S. Lewis called “good dreams that God has given to the human race.”
As such, you could include fairy tales in that category. When critics say that the gospel story is a fairy tale, they’re actually far closer to the truth than they imagine, but for a very different reason than they think!
I think you might really enjoy a book that I read decades ago called Eternity in their Hearts by Don Richardson (also available on audio books). He’s the same author who wrote Peace Child, which I think you would also enjoy.
He demonstrates how even the most primitive cultures have retained broken reflections of the truth that all of our common forefathers once knew. And he shows in both history and the Bible how missionaries who will find those gospel glimmers can make connections between tribal traditions and the Christian message to form the bridge that will lead the lost to Christ.
You can see Paul doing this very thing with the Greek influences you’ve specifically asked about in Acts 17:22-34. Richardson goes into the very interesting back story of the Athenians’ unknown God that Paul was declaring to them.
I would say that the big difference between your first hypothesis and the second is which story you’re proposing is the original, and which is the broken reflection.
I hope this will help you!