Actually, if you remove the 4 lbs for food are you already at less than 20 lbs base pack weight? Since the amount of consumables such as food and water often varies, most of us report pack weights without them- this is called "base pack weight". The conventional definitions are then:
>20 lbs heavyweight backpacking
<20 lbs lightweight backpacking
<10 lbs ultralight backpacking
<5 lbs is a survival exercise rather than camping, but there is a lunatic fringe that does it. They try to legitimize this by calling it "superultralight." :)
I have to admit, it would be nice to know what you're doing and where you are doing it. For instance if you're mountaineering or canyoneering then you might need the rope and biner- otherwise probably not. Short of those uses there isn't anything you'll need that parachute cord won't handle, and parachute cord is a HEAVY solution by our standards. Look at the guyline and bear-bag kits here in the BPL shop for ideas.
Most people post a 3-season gear list separate from their winter list- they tend to differ considerably. (Many would argue that a 4-season list is essentially impossible north of Mexico, thus the difference between a 3-season list and a winter list.)
As a 3-season list, yes, trust us, we can shred this... :)
Unless you are going to be gone for months, lose the sharpener.
There are those who would argue against taking a knife at all and just making due with the scissors from a Victorinox knife. (Just the scissors, mind you, not the whole knife.) But some people simply like their knives, so if you're one of those people 2.3oz ain't too horrible. But check out the Baladeo knives here in the gear shop on BPL for one example of a lighter knife.
There are many compasses available for well under 1 oz. Most are simple baseplate compasses without a lid or mirror, but you do NOT need a mirror for 99.9999% of the orienteering in North America.
Unless you are doing very long trips to the Alaskan bush you can make do with a much lighter FAK and repair kit. There are many discussions regarding them on this forum- I will not repeat them here. Many items in them can do double-duty, such as the tape, etc. Also, I would have thought that needle & thread would be included in the repair kit. Usually, if you really want to be able to sew an emergency repair you can just take a single needle with a large eye and use your dental floss as thread. (Assuming that you carry floss.)
If the fishing line is for "survival" purposes, I would just ask you how often you have needed it in the past. If your answer is >1 you should probably reconsider your hobbies. Leave it behind, unless fishing is simply something you enjoy in the backcountry. (In which case, check out Tenkara rods.) Also, you can starve for over 10 days without much physiologic effect beyond fatigue and reduced cold tolerance. Having water in an emergency is much more serious.
Safety pins could also be included in your repair kit weight.
Much lighter light sources are available, though for a headlamp I don't think 4.3 oz is THAT bad. But, really, how often do you use a light? Most people might use it to avoid stepping off a cliff during nocturnal potty breaks, but that's it. Most people here use a little LED light such as a Photon Freedom. They can be stuck to your hat brim with velcro to act like a headlight if needed. Alternatively, Fenix makes several very small AAA lights with clips that can be used to mount them to a hat brim. It is unlikely that you'd need spare batteries unless you are gone for months. I have a Fenix because I decided to standardize all of my (very limited) electronics to using AAA batteries, so that I could swap them around in emergencies. But I also have a Photon Freedom for shorter hikes.
You can decant any of your liquids (repellent, sunscreen, tobasco, water treatment, liquid soap, hand sanitizer, etc) into smaller containers. Small dropper bottles are sold here on BPL in the gear shop, but there are many others who sell them. Or you can re-use eyedrop bottles.
11 oz for a rain jacket isn't bad. You can get a reasonably durable one for 7 oz though. GoLite makes one. Fringe rain jackets can be less than 5 oz, but the tradeoff is that they're fragile.
The conventional wisdom here on BPL is that fleece is heavy and doesn't compress well. However, it does tend to be cheap, which is also a nice quality in hiking gear. If you want light, though, get high-loft insulation for your insulation later- either down or a high-loft synthetic.
If you're a hammock guy I think that there are lighter options. I think the standard Hennesey Asym is 44oz INCLUDING the tarp, and they make much lighter ones. Also check out Warbonnet. (But take this with a grain of salt- I'm not up on the state of the art in hammocks.) What kind of stakes are you using, and what do they weigh?
But you could drop POUNDS just by sleeping on the ground under that tarp.
4 lbs for a 3-season sleeping bag is pretty horrible by our standards. Actually, you can do much better than the 3 lbs that you aspire to, for that matter. We can gladly give you all sorts of fanatical fringe solutions, but if you want to stay mainstream look at the Marmot Hydrogen/Helium/Lithium line. The Kelty Cosmic Down 20 was also reviewed on BPL recently and is incredibly affordable for a bag of it's performance- about $100 IIRC. For a winter bag that is cheaper (but also rather heavier than most here will accept) the Marmot Neversummer ain't bad.
What sort of sleeping pad do you use, and what does it weigh? If you don't use one you'll probably want to get one. That'll let you carry a lighter sleeping bag since you won't be losing as much heat to conduction or convection underneath you. (The sleeping bag insulation that you lay on gets compressed and thus doesn't offer any benefit, so you usually need a pad under you or an underquilt under a hammock in any but the warmest weather.)
Why a firesteel? Will a Mini-Bic do? But if you're a firesteel afficionado then despite what others have said 0.9 oz ain't bad. The miniature one sold here on BPL is 0.81 oz.
There are much lighter packs. Personally, I like almost everything MLD sells, including their packs. An MLD Burn is 10-11 oz, but they make some bigger packs, too.
How long is 4 lbs of food supposed to last you? For 3 season most of us use around 1.5 lbs/day (with a range of about 1.2 lbs/day to 2.0 lbs/day).
2L is probably an appropriate amount of water- but water is heavy, 2.2 lbs per liter. If you're back east you could easily carry only 1L and restock as you encounter sources.
Was that brutal enough? I can be much more harsh if you prefer.