I want to edit the Track Title/Artist name displayed when selecting Time Stamp on the PLAY/EDIT screen.

Although you can not edit them on the PLAY/EDIT screen, you can edit them in the TRACKLIST on the FILE screen.
Follow the instructions below to edit:
１. Swipe left on the file on the FILE screen
２. Tap [Edit]
３. Tap [V] on the right side of TRACKLIST.
４. Tap Track Title/Artist name on the Time Stamp you want to edit.

If there is no Time Stamp on the file, TRACKLIST will not be shown.