I also had similar questions as yours, and I don't wanted to send any unnecessary documents.
Thanks for your post, Mine is also expiring in May and hence I am submitting the renewal application this week.
I want to know,
Q1)
Does it helps to minimize the chances of having secondary review by adding lots of supporting documents ? (Just a question, I wish no one goes for the long delay of secondary review).
Q2)
If you are also submitting the Passport photocopy, are you copying all your passport pages or only first 2 bio pages ?
Thanks