Hi,
In adiition, As per my understanding; COEJ, COEP, COSB, COSP, COSS are among the crucial ones in terms CO Objects and Line items.
They also do part of archiving object CO_ITEM so you might consider this side as well.
Secondly, you can go through the spool carefully (if not done) and understand any dependencies on other objects. N/w graphic is also kind of helpful to understand the FI dependencies.
Hope this helps!!
Regards,
Yogesh Soman.