I think you might be overly ambitious in your timings to meet the Dwarves & Scrooge & Donald, the ducks in particular took forever to get through M & G's last year.
We went to two parties & gave up after 50 minutes on the first night as they were having major problems with the photo equipment, but when we went back on our second party night we waited even longer due to the time that the ducks were taking with each set of guests.
The interactions were brilliant but they were only getting through 5 or 6 sets of guests each time they came out.
Good luck though & I hope you have a brilliant time, we would love to be back over the pond visiting at this time of year again but won't be back until next year.