All the data is anonymous by default, although you can volunteer to share excerpts and receive inquiries from Facebook if it has questions.
The consultation phase only lasts for six weeks as of April 1st, so you'll want to act quickly if you want to offer your feedback. There's no guarantee that this process will have a dramatic effect on the oversight board. However, it's evident that Facebook is determined to have a watchdog that reflects what users want. It knows that its existing content moderation leaves something to be desired, and it doesn't want an overseer that repeats the same mistakes.