The grace note in FED definitely indicates the manner to begin a trill. This allows us to read it, despite unclear notation, as a c2. We add a cautionary natural because of c flat1 in the L.H. part.
Compare the passage in the sources »
category imprint: Differences between sources; Editorial revisions
issues: Annotations in teaching copies, Annotations in FED, Authentic post-publication changes and variants
notation: Pitch
