Just to clarify, the Sentients are pooled/spawned prefabs.
These prefabs are having the COMETS object set on them immediately after spawn, by using Set FSM Game Object (which you taught me, many many months ago!):

Just to avoid any confusion, you can see the 'Prefab To Spawn' is 'New RedComet'. This is just the name of the prefab, but I'm calling them 'sentient' as the Spawned Game Object.
The spawned Sentient prefab can 'see' the COMETS game object, which has the array lists on it, so am I right in thinking that as long as the connection has been made, the Sentient
should be able to access the array lists on the COMETS object?
You can see on this screen grab above, the spawned sentients are added to their own array list on the COMETS object. When you start shooting one of the sentients, as its health drops it sends an event to all sentients on the array list:

This action works just fine, so the connection is there.