The moderators see all of the reported posts. All moderators are sent an email when a post is reported and it starts a thread in the moderators forum (one thread per reported post, with "replies" each time someone else reports it) so it can be marked as taken care of (or debated if its a grey area).
Adding a PM isn't likely to happen (especially if spam ramps back up) unless it is automated as it would be a lot more work to do that.
As for the delay in replies, it depends on who is on (from a computer as it doesn't work well to remove spammers from a phone) and has time.
I think the record response time is under 1 minute, but it can be several hours if everyone is busy tractoring.
Aaron Z.