So I already understand that when Spirit Ghouls are the already-in-decline race, they cannot make any conquests on the turn that the active race declines, but do they score victory points for the territories they already hold?
From the Spirit description in the Rule Book.
You may thus end up with two different races In Decline on the map at the same time and score for them both.
Going in to decline and conquering are exclusive events. The turn the ghouls go in to decline, they cannot attack.
If you have spirit as posed in the question, and the active race goes in to decline, then neither can attack as going in to decline is an exclusive event for the turn and after the decline phase is completed, the move goes to the next person.
This was also clarified by the developers with a small world clarification .pdf (http://templecon.org/13/files/boardgames/SmallWorld_FAQ.pdf)
Hope this helps, and have fun!