A bit late to this, but there are a few methods to reference the Interceptors from the Carriers.
Let's say I want to swap the model of the interceptors to probes.
Create a trigger with the Event: Unit Is Created.
Event: Any Unit creates a unit with ability Carrier-Hangar
Action: Actor-Send message "ModelSwap Probe" to actor (Actor for (Created Unit))
Note: The Interceptor in this case is referenced as the Created Unit.
Create a dummy Set effect. Name it Interceptor Dummy (for ease of reference)
Under the Effect: Create of the Carrier-Hangar ability, put in Interceptor Dummy.
Next, create a trigger with the event: Effect Used.
Event: Any Player uses Effect Interceptor Dummy
Action: Actor-Send message "ModelSwap Probe" to actor (Actor for (Triggering Effect Unit(Target)))
Note: The Interceptor in this case is referenced as the Triggering Effect Unit(Target).
In conclusion, both methods had the Interceptors' model being swapped with the Probes' model.