Yes, but look at how Call Lightning and Call Lightning Storm work. A one time investment will pay off for the next 5 turns with no further drawback.
Yes, but if a creature doesn't have resistance to the relevant element then there is no point. Also: there is further drawback, since it takes up a higher spell slot...now that you metamagic'd your level 5 call lightning storm spell, you can't cast your normal level 7 spell until you renew. Anyway, good night.
Slay Living, Wall of Stone ad Plane Shift would be my top 3choices.
Tala tries to gather all the dead guy's pieces together. N if I did get a Familiar throug a feat, would I count as a Lvl 8 caster from 8 levels of Assassin?