No, they wouldn't - I'll let Scott Manley explain.
Probably more about specialization and fuel types. For descent, the imperative for the Soviets was to avoid toxic fuels, in case of ingress into the cabin. So the descent module uses a peroxide based fuel. The only trouble with that, is the fuel has a shorter lifespan. If you wait too long, you end up with water and oxygen that is no longer useful. I prefer the philosophy of making a better capsule with a cabin that is perfectly insulated from the fuel system. It works very well. There was only one case of ingress, which was on an older design. And it created only a momentary issue for the human occupants.
Soviet designs are usually overdesigned, heavy and built to be maintained by simple tools, there's a story about an Aeroflot aircraft being delayed, the pilot told the passengers there was a fan blade at the front of the engine which was a little crooked, in the west this means the aircraft will be sent to maintenance and you need another aircraft to haul the passengers, not in the USSR, a mechanic walked towards the engine which, climbed into the engine housing, found the crooked blade and whacked it back into shape with a large hammer, he hopped out of the engine, gave a thumbs up and walked off, the pilot then started that engine, gave it full throttle for a few seconds, seemed to be pleased and just flew off without a hitch..
A small reentry module minimises the mass required for heat shielding and the parachute system. The orbital module can be relatively large as it doesn't have to reenter so the total habitable volume of 7.5 cubic metres is larger than the Apollo command module's 6.2 cubic metres. The total mass of the Soyuz reentry and orbital modules is 4.3 tonnes compared to the 5.8 tonne mass of the Apollo command module so the service module has less mass that it needs to accelerate during orbital manoeuvres.
Possibly, but they have had some quality control issues of late. The failures of Proton have almost cancelled it. They flew fewer Proton launch vehicles this year, their commercial workhorse, than any time since the mid 60's. Their designs are sound and they can no doubt figure what caused it and put in methods to prevent it.
Apollo had the same system of service, descent and specialist modules, it's just that the latter was stowed in the S-IVB adapter for retrieval in orbit (and of course Soyuz has only ever flown with the OM, whereas Apollo had the docking module rather than the LM on ASTP, with other alternatives proposed for Apollo-X before that became Skylab).
The LEM is a separate spacecraft and has no bearing on Apollo CM/SM stack. It just came up for the ride on the same Saturn V. It could have been brought up seperately in a 2 launch system. It wasn't used on all the Apollo flights, it wasn't used on any of the Skylab or ASTP flights
From what I've heard descent module is really crowded. they had to expand it a little bit when they started ISS flights as the restrictions on cosmonaut candidate size were smaller then than they were for ESA, JAXA and NASA.
An early Soyuz kit made the same mistake, putting crew couches in the OM.
