On The Neighbors, episode "Halloween-ween," alien boy neighbor, Reggie Jackson (played by Tim Jo), convinced human girl neighbor Amber Weaver (played by Clara Mamet), to costume up for Halloween, but there was a misunderstanding about who was going to wear what. As a result, both the boy and girl dress as slutty nurses with her referring to him as a “ladyboy.”
On Modern Family, episode "Open House of Horrors," Jay Pritchett (played by Ed O'Neil) feels like he is losing his touch with the ladies. Later, when he attends a Halloween costume party, he hits it off with a guest named "Sam," who is dressed as a princess. It turns out the Sam is a man (played by Rodney To) (see photo above).
On Suburgatory, episode "The Witch of East Chatswin," neighbor Noah Werner (played by Alan Tudyk) admits to dressing as his wife the previous Halloween. Not femulation-related, but neighbor Dallas Royce (played by Cheryl Hines) dressed as a Barbie doll for Halloween and her resemblance to the doll was remarkable.
You can view all three episodes on the ABC website.