My thought is, do you need 4 water bottles? I'm a water hog especially in hot weather and I'll only go through a bottle an hour at most and can stretch that if needed. If it's a supported ride and/or you pass through any towns, you should easily be able to refill water on the road in lieu of carrying that much weight with you. I didn't see one ESSENTIAL item (for most people) chamois cream. I lube up in the morning and then fill a film canister to take with me for a mid ride touch up especially in hot weather.
Rick