I would like to think so too, but I can't say since I know nothing about Erza. The only thing I do know is that her most powerful armor is "plot" armor Aside from that I would think that things would come down to how they stand without the aid of anything except raw power and feats. Is Erza's magic endless? Doesn't she need it in order to summon her gear? If she does then perhaps that would be a weakness?
No, her magic isn't endless. Her most powerful armor is plot armor, as you mentioned. She wouldn't be able to counter Haki, tbh. Zero would crush her easily.