We were on the Magic a couple of weeks ago and the only character I can add that nobody has mentioned is Dopey. One night outside the Walt Disney Theatre, Snow White and Dopey were together and you could have pictures taken with them.
Most of the time it was short waits of 5-10 minutes for pictures. The only excessive line I remember was the Princess gathering (Snow White, Aurora, Belle, and Cinderella are all there at the same time. It is held twice during the 7 day cruise. First gathering we came during the middle and the line was HUGE. Decided to skip that. We knew when the second gathering was being held and we walked by the atrium about 40 minutes before it started and there were already 10 people in line. So, I told my wife and the girls that I would stand in line and they can do other things instead of all of us waiting. When we got done meeting the princesses I looked and the line was huge again. So, you definitely want to do some planning for the princess gathering.
It is also very common to run into them in the hallways and they will always at least acknowledge you and many times will stop for short time. That's pretty neat.
One morning we were in Shutters (the photo picture place) and here comes Goofy walking through. He stopped and briefly kissed each of our girls on the head and headed into an unmarked door in Shutters. One of the ladies working there said that the characters use that door as an entrance/exit. 30 seconds later Minnie comes walking into Shutters and enters the same door. We stood there for about 5 minutes more and at least 6 or 7 different characters came into Shutters and used that door in that time. Every single one at least waved or high fived our girls and most stopped for a quick hug. It really made the girls' day.