That's actually a good point, because poison has to travel through the bloodstream in order to have effect, and it might get destroyed by the acid.
I didn't even think of that. I gotta love how those fights play out.
Poisons might work but they'd need to be poisons that work specifically by targeting parts that would make it unnecessary for it to touch the acid, or specifically crafted to survive acidic environments.
Before I go on with the analysis, I must say I love this fight conceptually. This is incredibly interesting and thought-provoking, and is actually very fitting conceptually for all parts involved. The Alien pursued and pursuing the Predator, the dynamic of prey and hunter, the conflict of the armed, cunning man against the mighty and nimble beast.
AP is, like most things of the match, really thematic. The Alien, representing the animal of the dynamic, is the stronger one, and not only that, but the bladed limbs, fangs and stinger further amplifies that advantage. Kraven, however, isn't that much weaker, and wields weaponry that can too minimize the AP disadvantage, and, aside from the stinged tail, is in general at a better range in melee engagements. LS has the Alien having a SERIOUS advantage, so if it gets its claws on Kraven, it ain't letting go.
Speed is equal, of course, but mobility and agility are interesting topics. I feel like the Alien in the original movies may have superior athletics, but this time, Kraven is the clear superior.
In general skill, I think it's pretty clear that Kraven is the superior one in most regards, although the Alien's natural ability and sheer instinctual capabilities shouldn't be scoffed at. Particularly, I can fully see a "stealth battle" happening here, with both fighters attempting to set up ambushes against each other, with varying degrees of success. Again, I'd give the advantage to Kraven, thanks to his ESP, but to be honest, it isn't something very detailed on the profile, so I might be wrong.
Now the interesting bit: Powers and their versatility. Kraven is, honestly, the more versatile one here, with his poison, knockout and stunning devices, and his general physical abilities. However, the Alien's acid powers are a very serious threat that can nullify many of Kraven's weapons, from his poisons to his nets. Not only that, but they are a sort of ability that ignores conventional durability, even if only through extended contact. There's also the summoning, that, if it happens, Kraven's dea, no questions asked. I'll assume it's something that would only be done in a given opportunity or to finish the foe off, but it's possible it could happen in any moment of the fight.
I'll bet my chips on Kraven. His smarts, combat skill and stunning equipment should be able to take the day over the AP and acid advantages that the Alien wields. A very awesome fight, though, and a worthy hunt for Kraven!