Some people find shells and old coins on the beach. In “The Light Between Oceans,” Michael Fassbender and Alicia Vikander find a baby and, well, finders keepers. They’re not the first characters to discover a surprise bundle of joy. “The Jungle Book”: In the 1967 cartoon and this year’s remake, wild animals discover a baby and, because Disney made both movies, decide to raise it as their own rather than eating it as a snack. “The Odd Life of Timothy Green”: Longing for a baby, a couple bury a box containing all their wishes in the backyard.