This is just good principle now that light sources are so tiny and powerful. You never know when you might have a real NEED for light in the dark and it is foolish to depend on one when you could add another with nearly no additional weight or space. The same goes for fire starting equipment, and useful mini-tools like keychain multitools and mini lighters. I have those on my ring at all times regardless of where I’m going. Why chance it when the discomfort is non existent?
OP: That hammock system is awesome. If you are in warm weather and a forested area or one where other object can serve as uprights it is absolutely the way to go. It isn’t a bad addition in areas you need a bag either. cozy in the hammok or use it for an emergency tent. I like MRE’s from the surplus store for food. They don’t require cooking (just add water and the chem pack heats up) and have loads of calories distributed into many items. They are not large. Use a Seal sack for anything that needs to be waterproofed. Rain gear is whatever you prefer. I roll up an oilskin coat in my packs and just deal with wrinkles if I need it. It’s sturdy, useful in nasty brush, and should last a lifetime. I do not carry extra clothing besides a second pair of good socks.
Do not skimp on the following: I’ll add a few links at the bottom.
Med kit. You can get an awesome small one for about 20.00 that will have everything you could need to treat any first aid type injury or mild illness.
Survival kit. Like the med kit, you can get or build an awesome, comprehensive kit that takes up very little space and weight. Hope you don’t need it, and be prepared if you do. Both of my kits are comprehensive and measure less than 6x6x2 when pack properly into their plastic cases.
Backup minikit. personal carry items. Mine is made up of a good multitool, a keychain waterproof lighter and keychain minitool. If you lose your bag somehow, at least you’ll have the basic tools to start a fire and work the materials around you.
Two mini LED lights. One should preferably be a headlamp. Addressed above.
Extra batteries for lights. Put them in the seal sack along with a new 9 volt and some steel wool. Again, redundancy in light and fire starting with little to no weight.
Mini tubes of bug spray and suntan product. Better to have then need.
Optional items:
If you have space or don’t mind carrying a bit of extra weight, a good lensatic compass is always useful but rarely needed.
In wilderness hiking I also carry a very small camp axe. The weight is worth the benefit. On well frequented trails this is not necessary.
A couple of tins of STERNO. This is great if everything becomes soggy. If that is too heavy or bulky for you, mix a tin of vaseline with cottonballs for waterproof fire.
I can fit all of the above into a regular shoulder day bag with room leftover. Minus the axe and sleeping bag it doesn’t weight that much, only a few lbs and has everything I could ever NEED in an emergency situation. I like to travel light in terms of food, and prefer to use my purification tabs or boil water rather than lugging it along. (I do keep one 16 oz metal bottle at all times though) If you have one of those frame packs you could easily carry this and more without a lot of effort.