Some elements of epic poetry reflected in the Odyssey include:
- Supernatural aspects, as it delves deeply into themes of gods and the afterlife
- A challenging journey filled with trials, such as when the characters are caught in a violent storm at sea
- A Hero demonstrating resilience
I think a motif can evolve into a theme as it accumulates greater importance throughout a piece of writing. A theme generally summarizes the central topic of a literary work, meaning that a motif, if further explored, could imply a theme in the narrative.
From what I gathered, Bradstreet led a somewhat privileged life in England, whereas John Berryman was named in respect to Mistress Bradstreet. That’s the extent of my knowledge, and I hope this information provides some insight or hints for you.