You can find debate no matter how far back you look.

I believe one of the better indicators of learning what the ECF's thought is to see what they canonized.

They treated the historical narratives as selective history, such that if it was "selected" then there is a good chance that it was selected for it's allegorical application. For example, Matthew 2:15 references Hosea and applies it both allegorically and literally at the same time.

Likewise, Paul, when talking about Adam and Eve, speaks of them as being both historical figures and at the same time Paul sets them up as prototypical for humanity in general.

When you go beyond the era when the bible was being canonized, you get wildly divergent views from pretty much the beginning. Most Gnostic sects would be considered wild allegorizers by those who are today considered ECF's. --So much so that they are recorded in history as heretics. Then you would have strong literalists like Eusebius, more middle-of-the-road guys like Augustine.

As far as the creation story in particular, you can absolutely trace one alternative to that debate very clearly back in time to a point before Christianity. If you read Iraneus, you will see him arguing against a specific view of creation for hundreds and hundreds of pages. That is panentheism, or the belief that the all (pleroma) existed before anything else in the universe, and was also the sum and substance of the entire universe, and then the highest virtues started fragmenting off the pleroma such as wisdom (sophia) and faithfulness (pistis) and then those virtues further fragmented into less sublime virtues, and so on... until you gt to our physical, 3 dimensional existence which is almost totally corrupt and nearly worthless.

It's all very essoteric, and I don't have as good of a handle on it as some others here may have, but the point is (as far as the creation story goes) ECF's could not be in the ECF club if they believed God was not a contingent being (if they believed that God would not continue to exist if the entire universe and everything in it stopped existing) But they could be in the ECF club whether they argued that the creation event was a literal six days or not. I don't think that particular topic spilled much ink, but the writings I do know of tend to take the timeframe as not necessarily literal while preserving the concept of God as a discrete and active agent who is separate from the universe.