If you can find points to talk about - like how it relates to the questions and how WELL it answers the question - then go for it. Personally, I'm not a big fan of song lyrics, as I did Coleridge and it was best not to do anymore poems and alike...But yes, it doesn't need much research and thinking, does it? The song is a bit cliched but it depends on the question, like when it asks how imagination assists humanity etc etc - After two sentences on what the song is about, you'll need to find two techniques to talk about and state what is said, how it is said and why it is said in that way, as well as linking back to the question at the end of the paragraph.
Another thing, why 8 texts? That's waaaaaaay too much for 40 minutes - You need 2 prescribed, 2 of your own and 1 stimulus...hmmm, get back to me on this one. I can also help with the structure of the essay if you like.