[Redeyes]

Some ideas to fill your open slots:

A/S: Shield of the Heavens, adds twist fate & charged body in a large area.

F/E: Summon Magma Elemental, as a water elemental but 2 crush attacks + Flame Strike, some protection, fire immunity/cold vulnerability and weak fire shield but no trample.
Con- Requires new sprite

F/N: Corpus Annihilō (Latin: Body to Nothing) as soul slay/bone melter but also deals fire damage in a small area.

F/S: Daystar's Blessing, adding flaming weapon, heat radiation and fire immunity effects as a self-buff. If flaming weapon doesn't work (no other spell does it), then fire shield.

E/N: Elemental Warding, as resist elements nature buff but in a small area, large with gem cost.