I think it's quite likely the same person and story. Their connection is referenced in the story. Wouldn't be surprised if Renda is where Erdely got the contact.
From the Rolling Stone article:
"'When did it happen to you?' Emily Renda asked Jackie as they sat for coffee at the outdoor Downtown Mall in the fall of 2013…"
http://news.virginia.edu/content/rendas-work-while-uva-students-changing-lives
Look at the people she is hanging around with