In an MLA citation for a poem from a collection that features several authors and has three editors, the name of the author of the poem should appear before the title of the poem.
Here's an example of how it would look:
Author's Last Name, First Name. "Title of Poem." Title of Collection, edited by Editor's First Name Last Name, Editor's First Name Last Name, and Editor's First Name Last Name, Publisher, Year, Page number.
So the correct answer is: before the title of the collection.