When your civilization grows up on a flood plain, you tend to have folk stories about epic floods. Civilizations tend to spring up in places like that because the flooding rivers fertilize land used for crops. So universal stories of floods are hardly evidence of a Big Universal Noah-style Flood.
The Church does not require a belief in a literal ark, whether you do is a matter of conscience. So in debates over the ark, be sure to distinguish between someone who is asserting that the ark existed, as a matter of faith. There is no debating this. But a lot of ark believers make the mistake of asserting that it was physically a possibility, and that draws fire from everyone from marine architects to historians.
A literal Adam and Eve as first parents off all humanity, genetic bottlenecks notwithstanding, I understand to be required belief of your faith.