They're both good AAs on both characters. I guess Filia would get more mileage out of 2HP since she doesn't have hurtboxes at the end of it like Fukua, and it's about the same speed as her 2MP, but the great thing about 2MP is that if they block it, you still have another normal to go through, so they can't land cancel your AA as easily.
Like, if you tried to AA with 5HP or 2HP and they blocked. As soon as they land they can punish you unless you're already planning on hitting Updo or something (which is another benefit of 2HP/2MP).
With 2MP, you can meaty them as they land so they're less likely to hit buttons.
Fukua's 2MP is really good because it has short startup and recov and she low-profiles with it, so you can AA pretty much every normal barring Parasoul j.HP with it (Yes, you can even AA Double j.HP reliably with it).
Also, 2MP is a launcher, so if you hit with it, you can go straight into your air combo of choice.