I think it still rin who will become obito key to tnj. After his revelation in ch.599 it become clear what his motive.
And if that's the case the question is: how?
What can Kakashi say about Rin that could actually make Obito rethink his position? Many speculated that she might've started loving Obito, but that doesn't seem to be the case thanks to this chapter.
Then again Rin dying by the hands of who she loves (Kakashi) is Obito's own interpretation of things based on his previous knowledge regarding Rin's feelings. Whether Rin still loved Kakashi to the end or not can only be answered by Kakashi himself since he's the one who was with her in the aftermath of Obito's "death".