No, they don't need to sign the pictures, but you need to put their full name and date of birth on the back of one for each of them. Just one out of each eight.
You don't need copies of his driver's license. That's what the passport and BC are for, to establish identity. What about copies of his school leaving certificates? I know those aren't strictly required for anything, because this is spousal, but I included mine because they established the background section for me: when I left school and when I was taking my accounting courses, so I included my certificates to verify those periods.
Other than that, I can't think of anything else right now.