OE
The first blank gives you a “stark contrast” with the Greek representation of these times as a Golden Age, so it should be something bad, even starkly bad. Dubious (warranting uncertainty or doubt) doesn’t necessarily mean bad, and rustic (rural; lacking refinement) isn’t anywhere near as negative as flagitious, which means “marked by vice.” The ancient Greek myths are about the distant or remote past. Antediluvian is the correct fit (don’t be misled into thinking of antediluvian as a trap—it does literally mean “before the flood,” and thus doesn’t apply to the Greek myths, but it also means “extremely ancient,” which is what you’re looking for).
The stories about the past—in the third blank—would be equivocations if each of them contained a mixed message; but instead it looks like the mix comes only if you are comparing Biblical with Greek stories. Allegories, or stories with a moral or political meaning, are the right contrast for “faithful attempts at reconstruction” and correctly match “expressing ... fears and hopes.” Platitudes (dull, trite statements or remarks) introduces a connotation of banality not indicated by the text.
Answer: A,E,G