Earlier quoted context omitted.
If the comment doesn't make it out of pending in a day, what happens to it and its poster then? Edit: Deletion is currently possible for less than that (2 hours?). Will this be different for pending comments?
Yes, deletion is possible for a pending comment as long as it's pending.
On a related note, the new system may prevent people from posting in the feature suggestion thread (https://news.ycombinator.com/item?id=363). Since it's already a special thread that never closes for comments perhaps comments posted there should not be made pending.