Lisa Jeanine Findley is accused of fabricating documents to falsely claim ownership of the Memphis estate and auction it off for millions of dollars.
In a statement, Courtney Kramer accuses Willis of prosecuting the case to "bring fame" to herself and says the trial is wasting taxpayer dollars.
The rapper's sentencing is scheduled for Dec. 12.
The singer and her co-defendants argue that the holiday mega-hit shares only "fragmentary and commonplace building blocks of expression" with an earlier song.
The rapper was arrested following an incident with a security guard.
"I regret they were included," the guitarist wrote of the "choice language" in the legal documents.
Though she won't force prosecutors to start from scratch, the newly installed judge reprimanded them for failing to turn over evidence to defense attorneys.
The case claims the earlier track was shared directly with the producer of Pitbull's song, who allegedly responded: "I love this song."
After cancelling all three shows this weekend following the disruption of the attack, officials in London say Swift's five shows there next week will go on.
The rapper was in the city to watch the U.S. men's basketball team play Serbia in the Olympic semi-final on Thursday (August 8).
