After playing a few times on Lunatic, SanaeA still steamrolls through spellcards. I attempted to play through with MarisaA, and I actually have to dodge things...which generally gets me hit or forced to bomb. Just to make sure I could actually do it, I captured all of the stage 5 and stage 6 spellcards on Lunatic, save the last one.
Messed up my MarisaA Lunatic 1cc right before the Last Word, but I had a total of 13 lives and too many bombs to count. Though some parts are harder, it feels like the game throws you too many resources. Even the last spells of stage 6 aren't invincible to bombs, so you can bomb the whole game with great success.
Edit: Before the stage 6 final spell is declared, that portion cannot be bombed.