And Mei also possesses katon, suiton, doton and fuuton.
Fuuton rasen shuriken, as other fuutons have a slicing or a stabbing effect. A substance like lava obviously causes different kind of damage, nothing suggests that he could take a hit from lava and live.
Also Mei's suitons are pretty huge, they're perfectly capable of pushing sandaime around.
You're right that Mei has no feats of being able to even use silent killing, but I for one believe she can, as she is the mizukage and clearly has most jutsu that most kirigakure villagers have.
Mei most likely has experience in fighting in the mist, which I doubt A has, at least not that much. Mei is bound to have edge while in the mist.
Again, nothing suggests that A has any special speed. You can of course provide scans of speed feats he has and I could change my mind about that.
Like i said if we go by that logic, A fought against 10000 enemies alone.
Can you imagine what kind of self awareness this requires ? His senses has to be top notch to keep up that many opponents without showing weakness. Considering he fought against them 3 nights non stop, he has to be a machine in literal sense.
They must've attacked him in groups of 20s, 30s at a time at least now you're telling me A can't keep track of one person just because he can't see her.
Do you think he kept all 10000 person on his line of sight all the time?
All of his senses must be extraordinary if he managed to keep going for 3 nights straight.
And I'm saying this for 3 times now. Boil Release consists of Water And Fire. Water is weak against Lighning. Yet that man stand against the strongest Wind attack which is his weakness. Lets not forget this is open space either. Boil can't hurt this guy, especially not in this location.
So if we're going by the hypes which Mei has so little..
A can fight against 10000 person at once which requires immense stamina, endurance and battle sense. His sight, hearing and smelling must be top notch considering he stood his ground for 3 nights. So Kirigakure no Jutsu is out of option.
He's gone toe to toe with 8 tails and said to be go directly against a TBB.
He can use Fire Release for medium range offence which Mei could counter with her Water release.
He can use Earth Release to counter Mei's Lava if he can't find a spot to run.
He is extremely fast so chance of him getting caught by Mei's attacks are pretty slim.
He has Black lighning which would be Mei's nightmare.
If we go by hypes, his only proper opponent would be Prime Hiruzen or Sage of the Six Paths.
So what i am saying is no need to turn this into some fanfiction, lets stick to the facts we got.