I'm sure that the characters are there the whole time. I know they were for the very late breakfasts. In fact, it was even better because there were less people as the meal hours were ending which meant much more character interaction.
We are planning to go back in August of 08 and will be making our ADRs for dinner a little later too. Maybe not that late though.
It is all a personal preference and depends who is in your group.
A personal story... Our last trip in July 07 we wanted to eat at Chef Mickey's. We never ate there before. I made my ADR for the first dinner opening.
There was a good and bad side to this. On the plus, it wasn't as crowded as I expected and the characters came around 3 times or so. They may make it only once if it is packed. That was a neat thing.
The bad side was the buffet was swarmed by people who acted like the place was going to run out of food or something. It was terrible. People were cutting the line, using excuses like, "I have a little kid with me." Well, who the heck doesn't at Disney World! One lady had her father cut right in front of me at the prime rib carving station saying, "he's too old to wait in line." The guy was in his 50's and stood there screaming at the kid carving because it was too rare! He wasn't too old, he just wanted an end piece which was cooked a little more and felt that his dining experience was more important that the 25 people who he just cut off! Totally embarrassing behavior by these people!
I think if you are able to avoid the initial opening, the line at the buffet will be more spaced out and the "feeding frenzy" we experienced might be avoided.
As far as timing goes. a late meal is good if you want to just pack it in after. You can get quite a bit done then eat. If The MK is open late, eating at 6 or so is good because you can head back in after to watch the parade, fireworks and ride a few things after.
I would check the park times to help you. I truly think the next time we go, we are just going to schedule dinners on nights where the park is not open late. You can eat at 6, go back into the park by 8 and enjoy a few hours of peace while the mobs are leaving for the park open late that night. This is especially useful at MK because it seems like it is open an hour or two later every night than the other parks, even during the off season.
That would help you with Chef Mickey's and 1900 Park Fare.
A better strategy if you have younger kids is to eat the later breakfasts/earliest lunches. That way you can get up early, do alot in a relatively empty park, eat, then take off and do something else (nap even) when the parks get too crowded. Your evening is then free!
This doesn't work with Park Fare if you want to meet Cinderella or Chef Mickey's because they have no lunch offered (if you don't want breakfast), but the late MK hours make up for it.
I know I rambled, but I hope it helps!
