I think the point is not so much denying reality as choosing which view of reality is the most Orthodox. Fr Seraphim was indeed influenced by "creation science", but the only reason he appealed to creation science, which was otherwise the preserve of Protestant Biblical literalists that had no interest in patristics, is because he genuinely believed that Darwinism was incompatible with patristic Orthodoxy. Since Darwinism is not just a philosophy, however, but a scientific theory supported by concrete evidence, he felt he had to challenge the scientific basis of it, too.
I think the place to challenge thinkers like Fr Seraphim is where they claim to be the authentic interpreters of the patristic tradition. It's not enough to show that the Fathers took Genesis literally. You have to show that the Fathers would continue to have taken it literally now in the face of new evidence that wasn't around then. I personally think this is a legitimate question because elsewhere the Fathers refer to the secular science and philosophy of their day, which means they were not in principle opposed to learning from non-Orthodox sources. Even Fr Seraphim admits that just because the Fathers believed in heliocentrism or other defunct theories of the world we don't need to believe them now. His case for literalism in Genesis rests on the idea that this is not a matter of defunct science but of correct Biblical exegesis, i.e. if the Fathers took Genesis literally, then this overrides any scientific theorizing to the contrary.
Objecting that the anus would not have served any function without the presence of defecation seems to miss the point. Why should it necessarily have had a function at the time? It's not as if the world was invented to make sense to you or me. If St Basil believed that the tiger got its claws and teeth in Paradise, but only in anticipation of the Fall and NOT because the tiger killed prey and ate meat in Paradise, he is obviously envisioning a situation where something was present that didn't have an immediate purpose, but only a purpose in the future. And as far as I know Fr Seraphim showed convincingly that the Fathers did not believe that sexual intercourse as we know it today existed in Paradise, so the command to be fruitful and multiply must have referred to some manner of generation that would now be physically impossible or at least is beyond our current understanding. However, if we are not taking the Genesis narrative as absolutely literal history, this debate is beside the point. The real point is that the passionless angelic life toward which we strive is fundamentally different from the carnal life we know now. My take is that Paradise is a symbol of this goal of our striving.
JRR Tolkien distinguished between allegory and applicability when discussing the meaning of his own works of fiction. Allegory is when there is a definite symbolism behind some narrative that doesn't in fact permit great freedom of interpretation. For instance, one might allegorize the tree of life as Virtue, but if allegory were the only correct way to read Genesis, it would mean that we would not be allowed to understand anything other than Virtue by it, even if it would otherwise permit different meanings. Applicability means that each reader can derive from it what meaning he wished. I have a feeling that the Fathers who argued for literalism may in fact have been trying to defend this greater freedom and applicability of interpretation. So, internal to the narrative, the tree of life should be understood as a literal tree. But when applying the narrative to our own understanding, we can consider it to mean virtue, immortality or whatever seems appropriate.