Way I see it, no. A zombie is someone who first died, and then was animated (and in some versions made aware again) by supernatural means.
Ms. Fortune swallowed the life gem before she was dismembered, which made her immortal. She didn't technically die (though probably lost consciousness due to the shock and/or pain of being chopped to pieces). She still has blood flowing in her veins (very much so!), doesn't experience rigor mortis nor decay.
So while Squigly is a zombie (death first, back to life later), Fortune isn't (no actual death despite Dahlia's efforts).