(1) Because people who have seen the code can't say anything about it, and people who can freely comment on it have never seen the actual code, all we can do here is to speculate, speculate, and to speculate. Therefore, here is not an answer, just a speculation.
(2) This is not the typical way I write C++ because most of the projects I work on allows exceptions, at least on a local basis (i.e. not crossing application boundaries), and the coding standard ensures that there are always appropriate exception catchers in the right place. This answer was written as if it is an interesting thought, not as a sharing of experience.
My opinion is that to avoid the issue of partially constructed object (or, "state"), one must first fundamentally change the way parameter (precondition) validation is performed.
The change is this: instead of validating and assigning parameters one-by-one, one must perform the complete validation of all parameters together, in a side-effect-free manner.
In addition to that change, the role of class constructor is also changed. Instead of handling both precondition validation and state initialization, it will "outsource" both to someone else; it will only retain the part of responsibilities that are "failproof" (not capable of failing).
For example, assigning a primitive value (e.g. integer) to a primitive variable is failproof, provided that the primitive variable has valid storage. Another example is the ownership-transfer of a pointer from one smart variable to another.
Some of the biggest advances of C++11 is that smart pointers (and many other things) are moving toward making at least some of the operations "failproof", by giving the option of isolating those "failable" (having the potential of failing) operations into separate methods.
Ultimately, however I must say, the "no exceptions" rule is sometimes impractical for at least some types of application development. How else would one prevent
std::bad_alloc without exceptions? Should the system crash-and-burn?
Mission-critical systems prevent out-of-memory issues by ensuring system-wide determinism in memory usage. Everything is preallocated; objects are merely placement-newed on allocators. There is a maximum number of instances prescribed for each type of objects; attempt to exceed the maximum will either be rejected, or result in the yanking of another less-important, not-actively-in-use object.
This, may be why we keep hearing those memes about "this enemy tracking system is capable of simultaneously tracking 256 different objects." When a 257th object wants to be added to the system, one of the least-important object must go. Since none of us commenting here have seen any of the code, this is just a speculation.