Fundamentalist / literal readings are not mutually exclusive with multi-layered interpretation. Why would you think so?
Sort of - a literal reading and multi-layered interpretation are not mutually exclusive, but Fundamentalist reading and multi-layered interpretation, as I understand it, are mutually exclusive because Fundamentalists accept Biblical inerrancy in an historical fashion. They believe the Bible to be perfectly accurate historical record.
For 2000 years Christianity's mainstream view of Jesus' life is both literal AND symbolic. Why shouldn't the same be possible for stories from Genesis?
This is tricky, because literal as I think we mean it and literal as the Catholic Church means, when talking about the Bible, are a bit different, though there is some shared territory.
Literal would be as the author intended. Catholics do not, for example, take Genesis to be necessarily historically true, although they might.
People often take it for granted that, historically speaking, Catholics have taken books like Genesis to be historically true. They think of Galileo and his heliocentric universe - but Galileo's primary support came from Churchmen, and his primary opposition from scientists
who were threatened by the theory of Copernicus.
Augustine wrote about this topic, but I do not recall where. If I find it, I'll give a link or source that can be referenced.