Do any ATOs have approved syllabi for SEP or MEP which includes training at night?
Any ATO may elect to conduct a part of its approved course at night - the ATO approval certificate does not include any restriction on when training may take place.
I believe the privileges of an instructor cannot just allow instruction towards Licence/Rating issue, renewal or revalidation - they must permit instruction of any elements of a Licence/Rating syllabus to anybody at any time.
I have no idea what this means or what point it is attempting to make.
An IRI may instruct IFR at night, not VFR
But the privileges at FCL.905.IRI do not specifically include instruction at night - the very reason that you say a CRI may not instruct at night. Are you saying that an IRI may, for example, teach a non-precision approach at night up until the point that the aircraft reaches MDA and/or IFR is cancelled but may not then teach the subsequent circle to land under VFR?
A TRI may instruct at night if the approved Type Rating course states it.
Once again, the privileges at FCL.905.TRI do not specifically include instruction at night. What is more, instructor privileges depend only upon the instructor certificate and not the course on which the instructor is employed at the time. A TRI certificate either includes the privilege to instruct at night or it does not.