I love the concept and would buy the book, though I am not a colouring convert.
I would be happy to hang those images, and they appeal to me.
I think the idea of including a few dark as well as happier themes is fine. People can go to them when they feel it fits with their mood, and skip them if it doesn't.
The clock to me represents the amount of time this disease absorbs, not how much I have left. So far it has taken almost a year of my life and many hours of each day.
I look forward to seeing where you go with this.