Ah yes, Danny with the skill advantage, AP advantage, Stamina Advantage, and Hax Advantage.
Tell me how Agatha wins here, because her fighting is melee only, and she doesn't utilize LS, making Danny just beat her ass into sandpaper with very little Agatha can do to stop him, AND he has the capability to blast her if needed!
This is a blatantly one-sided match
In my opinion It's not "blatantly one-sided" if you actually considered how Danny fights. Let's go over your points.
First off, skill... Where to begin, sure, Danny is more skilled but it's in no way shape or form noticable. He's no trained martial artist like his mother, he's a basic brawler who throws punches and kicks, and has been combated and defeated by enemies who are animalistic, so to say he has the skill advantage, doesn't hold much weight. Where dealing with a 14 year old boy who's overconfident in his abilities which gets him in trouble numerous times, he just possesses the basic understanding of fighting.
Next, the AP advantage, as pointed out above, it's only a 1.2x advantage so it's not noticable large, especially when you consider the fact that he's in character in this fight and it's a well known fact that Danny holds back against his enemies despite the danger they pose to him. So realistically, while our rules state he's going to try to win, he's not going to hit her with everything he's got, so the AP gap is not really a factor until he decides to get serious and given who he is, that won't be immediate.
Next, the stamina. True, Danny possess more stamina but it's not like he always manages it well. Even then I doubt this fights going to last hours. Realistically, one would have gotten a hit in by that time.
Finally, hax. True, Danny has more hax but then you'd half to understand how he uses it. He doesn't hold his intangibility for long periods of time, mainly using it to pass through walls or to avoid an attack before returning to his physical state. However, Danny himself doesn't always spam this even in the heat of battle, and even once called himself an idiot because he decided to take an attack head on and not use his intangibility. Regeneration is a slight problem but given how large her claws are, she could easily hit something vital when stabbing him. Finally, Possession, this is a solid win condition but it's not like Danny will bust it out immediately, he uses it on his non-ghost enemies (humans) to get what he wants but he's a more a fighter, and given how Agatha looks, he'd approach with energy blasts and such before possession comes into the picture in my honest opinion.
So to answer your question. I think Agatha has the capability to stand a chance. As to how? Simple, Her teleportation (as you state she spams), can easily confuse and catch him off guard and and a good stab is all it would take. Danny has intangibility but as I mentioned, he's not prone to spam it, and he's also stated aloud that he needs to pay attention more in his fights because it allowed his foes to walk right up on him without him knowing. So someone like Agatha who has teleportation, has a high chance of getting up on him especially if she puts the area in darkness.
Will it be easy, no, at the end of the day, Danny still possess strong abilities but they don't make the match one in my opinion. I wouldn't have made the match if I didn't think Agatha didn't possess a solid chance at winning, but since you think strongly that this is a one sided match and have more knowledge then I do on Agatha, I'll close this thread. I didn't think it was that bad of a match up, my mistake.