1. Containerizing passenger space.
Not a good idea, it would require a massive re-engineering effort in the structure of the cabin, since a whole tube is a much more reliable pressure vessel rather than half of one with a 90 degree angle where the floor meets the wall. You generate a ton of stress at those joints with pressurization cycles. Hard angles were in part what doomed the first generation of De Havilland Comets. You can possibly add a smaller, whole tube in the cabin area, but then you get the space of a narrow body aircraft & increase weight.
Reinforcing the rest of the structure of the aircraft if you remove the cabin area would also add in a ton of weight. We all know how a cylinder of paper can support many times its weight in compression, cut a big hole in one side and it will collapse. The survivors of Aloha Airlines Flight 243 didn't know if the floor structure of the 737 alone would be strong enough to survive a landing without having the plane break in two.
2. Meshed chairs.
The FAA requires that all aircraft chairs withstand a 16G impact in order to keep passengers safe. There's a reason why the seating is so heavy and bulky, it's to keep us safe during an accident. The seat structure absorbs most of the impact, so our spines and legs don't. Mesh chairs may be cool (both figuratively and literally), but I doubt they'll hold up to 1.5 tons of impact force (16 times the average weight of an American male, 191 lbs) without tearing.
3. Noise
The 787 is heading in partially the right direction to reduce cabin noise. Other than the air rushing by the plane, most noise is from the air conditioning units, and general vibration of the structure. Most planes use bleed air from the turbofan to pressurize the cabin. Basically you take some of the hot air from the compressor stage of the engine and send it through different parts of the plane (to the wing leading edges for de-icing as an example). A good part of this superheated air is sent to the airconditioning units which work to cool it down and direct it into the cabin. The 787 eliminates bleed air completely, and uses other means (mainly electric alternatives) for most systems. Additional insulation & physical isolation of parts that can induce vibrations into the structure also help.