Therefore, if you believe a CRI is entitled to instruct at night, you must also believe that all mandatory Class Rating test items can be taught/tested at night
That is arrant nonsense! Just because some elements of the class rating syllabus should sometimes not be taught at night does not mean that none of it can. The CRI is permitted,
among other things, to instruct for a class rating and the Regulation does not place any restriction on when this may be done.
Your contention, as I understand it, is that because the Regulation does not specifically state that a CRI may instruct at night then he may not. Would you, for the same reason then, say that an IRI may not instruct for the instrument rating at night or that a TRI may not carry out any part of the type rating syllabus at night (e.g. ILS approach)?
In any case, there is nothing to prevent steep turns or stalling being taught on those nights when there is a clear horizon or to prevent a PFL to, for example, a lit runway.