I enjoy Halloween and watching little kids dressed up in their newest fantasy whether it's a zombie or Superman or a fairy, and I strongly believe kids should dress up to get their tricks-or-treats especially since we dress up to give the candy out.
One year my husband and I slaved over a very special costume which allowed me to procrastinate on some research, but unfortunately on Halloween night, I was sequestered in the office frantically typing. From the office, I heard ding-dong, the door opening, "trick or...", and generally silence after that until the door closed. We had a couple of screamers, and I heard my husband quickly take off the mask to reassure the child despite the damage already being done. We also had one kid say, "OHHH! I know you! You're the Jack-in-the-Box!" The kid was sorta on the right track. My husband was completely silent, held a silver platter with Krabby Patty gummies, and had dressed in a red kilt, oxford shirt, knee socks, shoes, and a Burger King mask. We ran out of time for the coat.
I'm not sure what we might do this year, but I'm sure you can gather some ideas for your kids from this list of Instructables.