Ditto for me on needing a "team" to complete the achievements. I was actually going to use my "Mid-Season" team and sent an email to the site asking about sign-ups not working.
I got a short and sweet email saying that I can no longer sign up. (it would have been nice to have that posted on the front page or something - or maybe take down the "Sign-Up button"?)
Thanks in advance to anyone who is willing to part with their dummy team info!