Hi - We were there just last week, too. You can't split up your combo meal but you choose dessert and drink from the whole selection. Also, sometimes the combo plates give you a choice.
I also might add that DS got mac and cheese as a side and they counted it as a snack!
Try the Soarin' Crmeme Brulee - not quite the same as in the restaurants, and waaay too big - but pretty good nonetheless!