What are some good Halloween Themed Engagement Party game/activity ideas?

My Fiancees mom is hosting a Halloween Themed Engagement Party in our honor next week, but she put us in charge of the games. There will be all adults, no alcohol, no nudity, etc. We’re trying to find games/ activities that will get everybody mingling and having fun. The games/activities we have so far are:

-a "match game" where you pick a piece of paper out of a cauldron when you first get there, and the object is to find the person with the matching word (ex. gravestone & cemetery, bat & bell fry, vampire & blood, etc.), this is just to get the guests who dont know each other to begin mingling.

-A costume contest (we have trophys for best costume, scariest costume, cutest (not skankiest) costume, and funniest costume)

-Bobbing for apples

Id like to do a "digital SCAVENGER HUNT" where the teams will have to find & take photos of themselves with a list of items pertaining to halloween, and some that have to do with us. (ex, a happy jack o lantern, 2 names on gravestones that start with M & D-our names start with M&D- and possibly a photo of a member of each team sprawled on a cop car). Another idea is a "murder mystery" where we pull 1 person aside and tell that person they’re the killer. Everyone walks around a room and the Killer "winks" at 3-5 people, if the killer winks at you, you have to "die" in the most dramatic way possible. After 3-5 people "die" everyone has 1 try to guess who the killer is.

We need a game where we can give out 1st 2nd and 3rd place ribbons, please give me ideas! Thank you!!!