In terms of headlamps, there are lots of good lightweight/ultralight options like the petzl elite, which I use. Depending on your needs this can work great and does weigh a fraction of a typical light. Clothing can be tough, but using things like down for insulating layers works well, and limiting the clothing you bring is probably the best way to reduce weight. You can have a set of clothes that you wear while hiking, then a pair of long johns and a different shirt to sleep in, and that should still be relatively light. In terms of food, dehydrated is definitely the way to go, and for cheaper meals one can invest in a dehydrator and diy their own food. To cut weight on the cook system, one can also try out stoveless to see how that works, by using coldsoaking or other food prep methods.

Hope that helps!

"Not getting to the summit is not failure, it is an opportunity to go there again."
-Kilian Jornet-