During Moses's nightmare, Miriam is wearing pink (like she does throughout the rest of the film). When they arrive at the water's edge and the adult Moses sees his mother put his baby counterpart in the basket, Miriam is wearing orange.
When the plagues destroy Egypt, not a lot of monuments are shown being toppled. However, in the song "When You Believe", when the Hebrews are walking through the ruins of Egypt, there is far more damage and destruction of Egypt that what was seen in the Plagues. However, the entire breadth of the plagues could not be shown since, in the record of them, the plagues last a lot longer than a few minutes, leaving the possibility that we didn't get to see all of the destruction.
When Moses' mother, brother and sister are hiding from the Egyptians, they see a group of soldiers running past. However, the only things that pass are the soldiers' shadows - the soldiers have been left out.