Two great sounding projects, Anne. I too have found lots of success with primary school students in embellishing, expanding on, and/or rewriting existing songs.

It's a bit maddening, given all the current research on the role of the arts in student learning and engagement, that schools everywhere aren't using approaches like these. I do see a small shift though, at least here in the US, with many schools adopting an "arts integration" approach. We can only hope that it picks up more momentum.