Coo-Var Heat Resistant Satin Black Enamel MAY be suitable but it should be noted that it is heat resistant not fire resistant and we also assume it is not an open fire. Finally although it would appear dry, full properties are only obtained when heated above 220°C so some areas may never be fully cured if it the surfaces do not reach this temperature.

No.

Yes it can assuming temperatures won't exceed 600°C, please see remarks on painting / curing process in the product data sheet (downloadable from the product page).

Coo-Var Heat Resistant Satin Black should be fine for this as the exposure temp is 600°C.

Yes, but it must not be in direct contact with flames and not exceed 650°C.

Please also note: The dry film only fully cures after heating, slowly, to above 220°C for 20 to 30 minutes. Unless fully cured the film remains thermoplastic and sensitive to some solvents. The film may be cured in-service, some fume and light smoke generation is associated with the initial cure.

Coo-Var Heat Resistant Satin Black can be applied over other enamels as long as they are also heat resistant. Clean and lightly abrade to provide a key before over coating.

Yes on any areas that are not subject to direct flame contact and remain below 600°C.