I am looking for ideas for an elegant picnic for about ten people. The occassion is my wedding this summer. It will (obviously) be extremely small, and we are going to have it at Ottawa's Central Experimental Farms. Their greenhouse and ornamental plant section is really popular for weddings and photos. We were thinking that, afterward, we'd just have a small picnic, but I have no idea what we could have.

Here are the criteria:
1 - Make ahead. Since I'm not having it catered, then everything has to be made ahead of time, or bought.
2 - Preferably chicken or crab
3 - Can sit in a cooler for an hour.
4 - Served cold.

If anyone has some good ideas, they'd be very much appreciated.