Ok instead of having these 2 aspects, why don’t you combine the 2 and instead of just adding 2 to each type, have it double the amount that can be summoned.
Skeleton Warriors would summon 8 instead of 4, unless you use the skirmishers then it would be 10. For Skeleton Mages you would have 6 instead of 3.
So instead of having a total of 11 Skeleton minions (12 with skirmishers) it would be 14 Skeleton minions (16 with skirmishers) with the ability to free up one more placement for another Aspect.
I don’t think this would be to much extra for systems to handle and since most people don’t play the minion builds due to them not being as powerful, for us that do it could help in bringing them up in power.
Also you could call it Aspect of the Undead Legion.