1. My groom wore a suit and the groomsmen just wore matching pants and then a white shirt. They all wore the same brown flip flops. I actually thought it looked very nice.
2. My guests wore whatever they wanted on their feet. Some were bare feet, some wore heels, some just wore flip flops. That was more their choice.
3. My bridesmaids went barefoot. My sister didn't like it... but hey, I hated my dress at her wedding and I still wore it! Basically, if you want them barefoot, they should be able to handle it. Otherwise I did buy them all flip flop wedges. I figured that would look better than flat flip flops if the sand was too difficult to walk on.