I'm working on a character build designed to take advantage of the Elemental Commixture feat without help - but rather than being an Inquisitor, he will cast in tandem with his familiar, which will be using spells granted to it via Familiar Spell (with a metamagic cost reduced via traits).
I'd really like to do it with a spell whose subtype can be changed when you cast it, so that my familiar can provide whatever elemental power is needed. The easiest spells I can see to do that so far are spells like elemental speech or a summon spell, but summon spells are 1-round casts and Elemental Commixture requires the casting to be a standard action or less.
Right now, the easiest I can see doing it is using Elemental Speech (perhaps representing the familiar invoking words of elemental power to modify its master's magic), cast out of a third-level spell slot, since the +3 spell level adjustment of Familiar Spell will be reduced by two because of traits. I'd really prefer a lower-level spell, though.
Any spells that fit the "choose your type" option at a lower level than 2nd? They can be of any class - I haven't decided yet whether to be a wizard, druid, cleric, or other.