All I'm saying is that they're comparable to each other, not who would win in a fight. I also think that Mel would win but we still don't know about what Flash does at its full capabilities so it is still soon to make a conclusive statement.
It doesn't matter if Escanor is there. He still got trashed all the time by Mel. Unless he's on The One he isn't going to do much. Knowing that, I don't think Ludo relies 100% on that power, he has to have pretty confidence in himself to not be instantly trashed by Mel. We also don't know what time of the day it was when Mael "retreated".
How isn't that impressive? Her magic release alone shook the entire battlefield and made the Induras be wary of her (something that didn't happen when they were fighting the AA, even though Ludo wasn't going all out). She also did it pretty well at pushing them back, even if she had to be assisted at the end. Do you honestly think that someone who is far below an AA could do these kind of feats? I heavily doubt it, she may not have too much battle skill or experience, but that doesn't mean she doesn't have the power.
Doubt it, since the Gods were far stronger than them and I don't see how Mel could be the only one to tank all the attacks. Besides, Eli was injured also, meaning that she had to at least tank one attack coming from them, which further supports Mael's statement. Regarding to your next point:
https://www.mangareader.net/nanatsu-no-taizai/233/16
Elizabeth: "With my power as it is now, I may not be able to stop him if he fully reverts."
She is clearly saying that her power isn't fully recovered, even with her memories being awakened. I have a question: who do you trust more regarding Eli's power: Merlin or Eli herself? I think the answer is pretty clear. At least for me.
Even if she did it wouldn't have had any effect so I don't know how that makes her look that bad. Not to mention that she is indeed still nerfed. Finally, how was her healing pathetic? Had not being for her, the Sins would have died multiple times in that fight.