Some info on the third and fifth act 4 prizes (possibly a PSA)

This might be known to most people by now but the Grief Counselor (3rd prize) has a 24 hour task which takes place at the CoE Championship Arena (5th prize) however, the task doesn't appear until the arena is placed and built. I only found it out last night when I unlocked the final prize and seen it on a post from another site. I also think that if anyone is working towards getting the arena should be able to unlock it after the event ends tomorrow but I can't be sure of that.