Fair use for poets, demystified

Pat from American University's Center for Social Media sez, "We're excited to announce the launch of a
Code of Best Practices in Fair Use for Poetry,
cofacilitated by WCL-AU's Peter Jaszi, UCB's Jennifer Urban, Kate Coles from the Poetry Foundation, and Center for Social Media's Pat Aufderheide. The hashtag is #fairusepoetry"

Why would poets need fair use? Consider:

Mark Taylor has been asked by a major press to assemble a collection of the essays on poetry he has written over the years and add several more to make a book. He can't decide what selections he needs to license, and which ones he can use under fair use. If he licensed everything, he would be paying thousands of dollars more than he would ever see in royalties.

Julie Blake decides to do erasures–taking words out of existing poems, and so making new ones–of the poems from her own collection of sonnets. She thinks the new work is both an evolution from and a critique of her earlier work. When she places the collection with a new publisher, the publisher of the sonnets claims copyright infringement. Does she have a fair use claim to do what she did?

Kurt Flanagan is a collage poet, making poems out of bits and pieces of existing work. His new work addresses war in the first decade of the 21st century. His book-length collage poem draws on news sources and also on literary sources, including but not limited to poetry. One of the poets whose work has been used in fragments sues for copyright infringement. Does he have a fair use argument?