Hi.
If prefabs are preset in a Scene its ok to reference directly to other fsms/GO
But if prefab would be created @runtime, then its a no no.
You can use a global tho, but you should minimize using globals.
Usually i have a object with some fsms (Data / array / reference to other object / etc.
@start i will place this object into the global so i can easily access from other objects.
Then on that data fsm i will have all the data that i need (score / lives / reference to other objects / etc.
for reference to other objects i would only need to use 'find gameobject' once!
Then if another fsm/object would need this i can use "Get Fsm Gameobject" and get it from the data (Meta) object
This way i only need 1 Global and would only need to 'Find' objects once.
There are many 'Fsm' actions available, and even more on the
Ecosysytem