After drinking the potion and shrinking, Alice has no shoes. From then on throughout the movie she sometimes wears beige flats, usually during dance routines and when she's walking or running on rough surfaces. At other times she's barefoot.
During "A Nice Girl Like You" when the woman "riding" the knight is lifted up, it's revealed that the knight's pants are still fully up, revealing that the sex is simulated.
When Humpty Dumpty is falling from the wall after the song, it's visible that his "ding-a-ling" is part of the costume and is not real.