Unrelated to those arguments, I wonder what made you pick the schools of magic that you picked? Ie, Alteration, Divination, Elementalism, and Necromancy? What about Abjuration, Evocation, Enchantment, Illusion, Thaumaturgy and such?
because Kael designed the arcan path around those techs, thus creating groups of mana spheres, linked by tech, and with the 4 "arcane" towers.
as a side note, elementalism is not a mana sphere in FFH or it's modmodmods.
Fire is a sphere,
ice is another,
force is another sphere,
shadow...etc
lastly :
Necromancy is a bad name but it encompasse all the dark mana spheres : entropy, death, shadow, chaos :all that sow destruction.
Divination is all that is linked to a higher self /more spiritual self : mind, spirit, life, law, sun (what is sun doing here? EDIT: because sun mana represents LIGHT )
Alteration is all modifying the existant + less spiritual : body, enchantment, nature,
Elementalism is the control of the wild elements : fire, water, earth, air, ice (maybe ice should be in necromancy due to Mulcarn being as much a destructor as Agares, Esus, Bhall and Camulos ; or maybe it is the opposite of fire...)
then you have Force, dimensionnal, creation that can be spread around : force and creation in ALTERATION and dimensionnal in .. divination?
and then there is Metamagic that is a school in itself.
(How come I have 21mana sphere and Dagda has no mana ... thus 22angels... there should be only 21.. does that mean that dimensionnal is Dagda's Mana sphere?)
If I were to change it I would have positionned the 21 mana spheres in 4 groups of 5 + metamagic.
alt : body, creation, enchant, force, dimensionnal,
div : law, life, mind, spirit, sun
Elem : air, earth, fire, water nature (IIRC in taoism there are 5 elements ; air, earth, fire, water and wood ; then vitalize should become a creation spell and Nature 3 be "summon treant" or something like that)
necro : chaos, death, entropy, ice, shadow