To teach for an IR you have to have the IRI qualification, that has nothing to do with being an FI(R).
No you don't and (in terms of this debate) Yes it does
To teach for an IR someone would either have to have an IRI
or have Privilege (g) added to their FI (or both).
Without 800 hours IFR an IRI is not possible, so the question remains: Would any Competent Authority grant Privilege (g) to an FI with Restricted Privileges?
I think not ......... but happy to be proved wrong