Krellnus- The dragon was subject to "hit only on 6's" since it fights in the challenge as part of the character's mount (and annoyance of nettlings says the treeman ancient can only be hit on 6's in a challenge).
boogeyman- I'm not sure! They said they might throw all of the characters in a pit in sort of a free-for-all, or it might be 1-on-1 matchups. Unfortunately, it looks like my wife and I have another commitment that evening, so I might miss it :-/
Chibi- Thanks! I appreciate it