When we did it, we were seated at 8:05a and were done and out the door by 8:52am. We got multiple visits from several characters, took about 2 trips to the buffet and still made it in this little time. I remember complimenting the mgr on how efficient things ran and he said they know people with the first couple of seatings really like to get out by park opening. While lunches and dinners tend to last longer, we've found it very rare to have a character breakfast to go past the 1 hr mark.