Realistically the essentials for an individual would be

Lightweight sleeping bag
Decent bivvy bag - army ones are good cos they're huge, cheap and work.
Thermarest thing 3/4 or cut down roll-mat
Dry kit for sleeping in
hat/gloves
headtorch
Tarp/bungees
Food
Hipflasks with choice of warming beverage...
Waterproofs
Warm jkt

Then you could share everything else out - 1 stove between 2, 1 first aid kit for the group etc etc. To save weight even more then you could trim down the bike tools etc so there's one pump, one shock pump etc in the group so you don't have 6 people all carrying their own...