I think each section could be its own little image, completely separate from the rest. That might be easier than trying to tie them all together with one theme. Can't wait to see the finished work!
buy a packet of labels ( the little ones with strings) give them to random people, ask them to do what they wish as long as it is positive, pin them to your canvas by their string. open your window an let all that positivity float...
I'm going to experiment with this... will tell my children, you can paint on this and then see what they come up with.