There could be characters like Hera Syndulla. She is often associated with Kanan and might play an important role in the graphic novel. Maybe Ezra Bridger could also be in it as he has a connection to Kanan in the Star Wars lore.
Whether the Kanan comics are canon is a matter of debate. Some aspects might align perfectly with established lore, but there could be elements that don't quite fit. It's not a straightforward yes or no answer.
Well, it's a bit complicated. The determination of whether the Kanan comics are canon often depends on the decisions of the creators and the broader narrative context. Sometimes new developments or retcons can influence this status.
Since I don't know the details of this 'ghost kanan story', I can't say for sure who the main characters are. But surely, Kanan, the ghost, is likely to be one of the main characters.