The written guide the researcher uses in writing the research paper is the "outline" although it should be noted that researches use many different things for guides.
I’d say:
I had a hard time deciding whether to write an essay about the works of “Eudora Welty, Joan Didion, Gwendolyn Brooks” because the rest of the punctuations doesn’t make sense.
But actually it should be:
I had a hard time deciding whether to write an essay about the works of Eudora Welty, Joan Didion, and Gwendolyn Brooks.
(Without the quotation marks and inclusion the word “and” before “Gwendolyn”)
A structual element for a poem would be stanzas. Hope this helped you a bit.
A colon suggests that there will be a list that will follow it. Using the words 'such as', 'for example', and 'including' in a sentence also directs the attention of the reader to a list. It will be redundant to use a colon after the word 'including' in a sentence.