Chook Me!

My son is turning 1 on Oct. 29th. , two days before halloween, what do you think of a bday/costume party? This question is for all the experienced parents who have thrown successful and fun 1st birthday parties for their babies. I am throwing a big party to celebrate my only child who is turning 1 in october. My house does not have a lot of parking for the big family that we have. Family and a few friends will be a party of 80. eeeks. So I just booked the 2nd floor of Sonoma Chicken Coop which will hold 100 people comfortably and we will be having buffet style dining. Since there will be about 18 children at the party. Do you think it would be a cool idea to have a costume party/bday party? Have all the kids/babies come dressed up? Any ideas on a few budget friendly activities for the children ? Any thoughts are appreciated. Thanks :)