The suit does not contain its own life support system. It is ventilated from a blower or, in case of a decompression, pressurized bottles within the spacecraft. It also does not have any meteoroid protection, and it tends to balloon when pressurized, restricting movement.
Yes. Sokol suits are suits that are highly specialized to the Soyuz spacecraft. An easy example of the specialization is the extra room in the hindquarters region to accommodate how far they have to bring their knees in when sitting in the couches. The American suits (by which I assume you mean the ACES suits), were not designed for this purpose -- they ...
Yes, the Sokol suits are provided with a ventilation unit for use prior to ingress into the spacecraft. "When worn on the ground, the suit is attached to a portable ventilation unit —a hand-held device that supplies air to the suit, cooling it first with an ice filled heat exchanger."
This is a training version of the unit.
As far as I understand this is just a new overcoat as an additional insulation for cold environments, underneath wich they still wear their usual Cокол suit. It consists of several pieces which can easily be removed by opening some velcro strips.
I haven't found many sources regarding the technical details of the SpaceX IVA suit, the best site I have found so far are close up photographs by Tim Dodd: https://everydayastronaut.com/up-close-and-personal-with-spacexs-space-suit/
Based on this pictures I will try to answer those points:
The joints: On the pictures there are special folds visible at the ...
The Sokol suit does not use a hose for gas inlet and another for outlet. There is no outlet hose.
Gas exhaust flows through the blue pressure relief valve at the centre of the chest; this valve also regulates the pressure of the suit.
Hoses for air and emergency oxygen are connected at the left abdomen of the wearer. See the dual hose at the right side of ...
This is a disposable spacesuit (Made-to-order gctc.ru/main.php?id=4813). I didn't manage to find information about any benefit in reusing any of its components. The next version spacesuit (Сокол-М) will be reusable.
"The new spacesuit can be used for 10 flights, it will be reusable,
with the ability to adjust to different parameters of the cosmonaut's
There is also a blog entry by Samantha Cristoforetti from Soyuz TMA-15M:
After depressurizing the vestibule, we observed for a few minutes the pressure indications for the descent module and the orbital module of our Soyuz: both stable, so there was no obvious, fast leak. (Not that we were expecting one!).
Of course we needed to check for a slow leak ...
TLDR: Crews for 1 bar missions, including Soyuz, don't seem to have ever used pre-breathing. Earlier missions that were headed for long-term lower pressure environments did, as do people doing lower-pressure space walks. There's some evidence that the risk of high-oxygen pre-breathing was considered larger than the risk of decompression sickness.
There's an interesting blog entry describing the return to Earth for an earlier expedition.
Here's a quote from the most relevant part:
Gennady, Andreas and Aidyn will put on medical telemetry belts and tight-fitting shorts called the Kentavr to stop blood from the legs flowing to the head during reentry. Afterwards they will put on their Sokol pressure ...