Final answer:
The information provided does not clearly identify Thomas Bowers and Elizabeth T. Greenfield with provided references that include an oil painting attributed to an unrelated individual and a portrait by John Singleton Copley of Mrs. Jerathmael Bowers.
Step-by-step explanation:
The individuals mentioned, Thomas Bowers and Elizabeth T. Greenfield, do not seem to be directly related to the provided references, which include an oil painting, a portrait by John Singleton Copley, and academic works by various authors. Therefore, without additional context, it is not possible to accurately determine who Thomas Bowers and Elizabeth T. Greenfield are, in relation to these references. It is recommended to seek further clarification or additional information for a more accurate response.
John Singleton Copley's portrait of Mrs. Jerathmael Bowers relates to the history of American colonial art and the influences of European artists like Sir Joshua Reynolds. Additionally, the inclusion of figures such as Lady Caroline Russell connects to prominent historical figures and ancestral ties to Princess Diana and Winston Churchill.