I think your destination is awesome! My fiance and I discussed getting married at Lake Tahoe (in the winter) before we decided on a summer wedding in the Dominican. I really like your ideas and think you're on the right track. You might still want to consider including aspirin for hangovers, band aids, or other hangover/first aid related items if you think you need more items. Also, a small bottle of lotion might be good since skin can get chapped in the cold weather. I love the mittens idea- so cute! The OOT bags can be as simple or extravagant as you want, your guests will love them no matter what...good luck!!