Could you use features on spells like elemental savant's focus (fire) to increase non-fire spells? Since its mixing features to gain the best spell
Unless elemental savant has an ability that makes all thier spells have the fire subtype, I would have to say no. It specifically says spellcasting parameters of spellcasting classes not of spells themselves.
At work atm, ill try to explain that better later.
My question is though, can anyone see a reason to use this advancing a divine casting class? Except possibly item creation.
Speaking of item creation... If as per my above build with the one level of cleric, could I craft a wizard item and call it a cleric spell to have a caster level of one and thus drastically reduce the cost?