I think you are on the right track, but I think you also have a bit of overkill. But first, how many days will you be out? I thought that gear wise, your close, agreed, you don't need two lights, and you could scale back on both GPS, and compass, but depends on exactly where you are going.
Clothing IMHO is a monster list. You have a list of clothes for all 4 seasons, with changes as well. Many of your clothes do double duty. A good question to ask yourself is how many of these clothes can I wear all at the same time. Whatever is left, don't take. Rain gear doubles as wind gear, which doubles as a warmth layer etc. Wearing your long johns under rain gear is like haveing fleece on etc. Get rid of the clothes and you will be more flexible, and lighter.
Probably the best excersise will be after you get back home, take your gear and put it into two piles. One, gear you actually used/wore/needed, and two, gear you carried around and just repacked all trip long. Then make a serious decision on wether or not that gear should be going with you again.
With regards to first aid/navigation/filtration items & possibly tent & stove/cook kit, these are or could be shared gear, and within your group, should be singled out as to not bring doubles and triples to make it light and usable. on a weekend trip, do 3 of you really need to all bring multitools? Or 3 first aid kits? I like to be prepared, but the best tool is between your ears.
All of these comments should be taken with a grain of salt, as each trip, and each area has its own parameters, but really force yourself to be disciplined. Good luck!