LA - Your arguments are becoming more and more convoluted as you insist on reading requirements and restrictions into the regulation that simply are not there. Your contention is that a CRI cannot instruct at night because the privileges of a CRI certificate do not specifically say that he can. It is true that a CRI cannot instruct for the night rating but he can give any instruction within the privileges granted by FCL.905.CRI either by day or by night (provided he holds a night rating or night qualification). For example, he could quite safely conduct differences training for VP props or SLPC at night, or some parts of the MEP class rating.
In the case of the class rating, there might be a restriction imposed by the ATO under whose approval he was operating but this is a matter for the ATO as the approval itself does not restrict instruction to daylight only. Differences training, however, does not need to be done within an ATO, nor does it need to be approved and so, in this case, it is entirely at the CRI's discretion when he conducts the training.
Similarly an IRI is not constrained to teaching only under IFR by night - for example, there is nothing to prevent him from conducting the whole of the BIFM at night under VFR (apart, perhaps, from the instrument appreciation aspects) . The same applies to a TRI, who may choose to teach any part of the type rating syllabus at night, with the approval of the ATO under whose approval he is operating.