This was difficult to understand.
That said, if I understand you, then, yes.
Referencing anything inside of a Blueprint requires you to reference that Blueprint.
So, if you are referencing “is_dead?” in the Blueprint “BP_Melee_Enemy”, then you can also reference “is_attacking?” or “is_staggered” etc., assuming they are variables in this blueprint.
If you mean, do you have to re-reference blueprint variables in differing EVENT_GRAPHS, then yes, you do.