Going back to the original post, I suspect the basis of the question may relate to an insurers stipulations on who else can fly an insured aircraft other than the owners. In our group, the policy specifies the same list of instructor types as indicated in the first post. Therefore, I am tempted to conclude that insurers are stipulating that the aircraft is insured for instructors and owners, obviously, once they are signed off. The policy needs to cover the period where the owner is P1 u/s whilst undergoing differences training etc.
In other words, the policy is simply saying, "an appropiately qualified instructor".
In this scenario I would have thought a CRI would therefore be covered by a policy.
However, if the owner does not yet have a licence then clearly the CRI would not be covered, as he would not be qualified to instruct ab-initio.
I'll phone our insurers tomorrow and specifically check if policy covers CRI's.