Halloween Costumes for 24 m/o and 2 m/o

Shelby
My nieces have their first and second Halloween coming up!!! My sister in law has asked me to help her brainstorm costume ideas.
What have you done in the past, or you think is cute, for individual or pair costumes for infants and toddlers?
Feel free to post pics, or go off topic to share Halloween pics of your little ones