I'm trying to find a list I provided to our Flood Team volunteers without much luck. Essentially a change of clothes, pants and socks for three days, wash kit, personal first aid/boo boo kit, any personal medication, spare glasses rather than contacts. I note you mentioned shared sleeping bags as an alternative a lightweight duvet type thing woobie/poncho liner variation on a theme might do, waterproofs, insulation of preference, hat and gloves with spares, food of sort be it muesli bars, chocolate, tea/coffee, sugar, hot chocolate, cup a soups, battery/battery pack, head torch, multi-tool.