Anyways to end this back and forth I'll bring up both my points and my qualms in one post.
Please show feats of Erza oneshotting other 7-Cs with said AP boost because at this point Hiei's boost is superior via feats. And range is a non-factor since they have the same range.
Furthermore, Erza can only use one armor at a time. If she uses the Flame Empress, she cannot use another armor to boost her AP/dura at the same time.
Speaking of the Flame Empress armor, it's not that helpful. Firstly, Erza attacks with fire while using her flame empress armor. This isn't going to help much as Hiei himself resists fire. Furthermore, the Flame Empress armor should be equal to the Kuro's armors which also resist fire. And guess what? Hiei was able to bypass this resistance with his Jao Ensatsu. If believe that Erza's fire resistance is superior to Kuro's, feats and scans would be appreciated.
If anything Kuro's should be considered to be better because no-selling fire attacks is far better than halfing their AP but ok And finally, the Flame Empress armor only halves the AP of fire. So even if you think that she resists Hiei's Jao Ensatsu (which she doesn't), it'll only be halved. Half of a oneshot is still pretty strong.
You say she has resistance but it's not even on her profile :^) If you think she resists, make a CRT. And even if she has resisted it, what are her feats of resistance? There are levels y'know.
As for Hiei, his ruthlessness gives him the edge in combat. Has a
pseudo-substitute ability that allows him to feign enemy attacks.
Shown even more here so saying he is doing it via speed is incorrect. If Erza decides to play the range game, Hiei's own range should be enough and the enhanced senses granted by the Jagan is able to see everything that she would do and would be able to counter accordingly. His Jagan abilities such as Clairvoyance, Mind Manip, telepathy and memory manipulation definitely give him an edge. Higher combat experience and I'll just assume they have equal skill. And because she's a human, Hiei would be far more willing to go all out from the get go.
Also, while I won't argue for it yet, there is enough evidence that demons are invisible to people. I have sufficient evidence but I'll make a CRT before I bring it up.