I wondered the same. I think they are. You can see how the pool is very cramped and follows the curvature of the submarine hull.

I wondered as well, but it seems entirely plausible. This thing had about the same crew size as an Ohio class submarine but more than double the volume.

This class of submarines was designed to spend a long time underwater on patrols. The problems faced by the crew are comparable to problems facing long term space missions, except there was higher chance of returning to port.

Because of that, Typhoons were designed with crew comfort in mind, with lots of amenities, ensuring crew performance after several months underwater.

That's the rest room next to the sauna, and yes, it's inside the sub.