For the first and second hint I have shared a video with you. I just wanted to point out that the hint could be hidden in the title of the song, the band name, the name of one of the Disney princesses, in of the fairy tales, in the lyrics of the song, etc. Just to make it all easier for you :-)
For the third hint I will share another video with you.
And I would also like to share a random thought with you; Dwarves are really secretive and won't even tell you their real names at first. They often use Westron names. So, you can already feel it coming, don't you? ^^ What if Thorin is not really Thorin's name? Why would the Company tell their real names to a halfling they have never met? Think about that when you go to sleep tonight!
Anyhoo...
On to the fourth hint:
'The next book is already taking place'
And that's it for this author's note! Just two/three more chapters and this book will end!