Thank you so much (hopefully you didn't rage too hard), and I'm glad you enjoyed the music!
Regarding the usage of last cup of coffee, LilyPichu has said that her music is free to use (see her x or subreddit), and since my usage of the song is in the form of non-commercial transformative arrangements (I'm not actually playing the original song), the music should (hopefully) fall into the category of Fair Use regardless.