One thing I'll suggest while I'm thinking about it...before hand, contact all the attendees and suggest bringing to the meeting family photograph albums. Everyone will be surprised at how a "face" will suddenly turn up 2 generations down the line!!! Seeing your own self dressed in a dress with what looks like the rear end of a horse following you and huge, massively stuffed sleeves and low cut front will startle the hot dog out of your hand!!! Or seeing your own face looking back at you while dressed in a shabby uniform and clutching a long rifle might bring a tear to your eye.
And have family bring photos they have no idea of who was who, and stick them up on sign boards with 3x5 cards underneath, just in case someone can name and date them.
My DH's family did that and a lot of unnamed pictures were named and often given to their closest kin.
Good luck....