Looks like I am not done with the OP of this thread. I've unlocked the Cucco and it doesn't share the challenge list of Ganon, but has its own list added as a separate challenge mode. This means that all challenges have to be unlocked again. I'll probably add a little extra section to the OP once I've played enough with the Cucco.
Achievements that I got recently:
38. Saved 500 allies. (This one took a ton of time. Thankfully I finished it before I had to grind for it.)
39. Completed hero difficulty in legends mode. (Legends mode complete!)
40. Killed 100 enemies with a special attack. (This is easy in Ganon's Fury because of the range of his special attack. Hitting anywhere between 100-130 enemies is a breeze, something that I didn't manage with any other character during normal play. Well, the Cucco can do it easily too, but by the time I unlocked it, I already had this achievement.)
Four achievements left: All A-ranks in Ganon's Fury, all A-ranks in all challenges, 100 amiibo gifts, all of the previous 43 achievements.