I am assuming all the icons will be unique though, else it may lead to a lot of confusion

I think this might just be a programmer's way of (over)thinking it : "the users are unique, so the avatars must be unique, or chaos ensues". In actuality it will just be mildly confusing at best, but nothing earth shattering. You still have the name next to the avatar for reference, as well as the project, and with several dozens of them, most will be different still.