I think it's possible that Meghan could have wanted to draw parallels between herself and Wallis.

Both Americans, both divorced, both married to men willing to give up everything for the woman they love. Both victims of the jealous Windsor women (Wallis vs Queen Mum, Meghan vs Catherine).

Andrew Morton's book about Meghan compared the two women. Wouldn't surprise me if Oprah mentions Wallis.

I should mention that I believe that Meghan and Harry knew in advance what questions they would be asked, so if Wallis is mentioned in the interview, for me it would be proof that Meghan deliberately copied her look in that photograph.