Well, enough derailing for now
I'm leaning towards Jason for now:
With speed equalized, Jason's teleportation gives him an advantage in maneuverability, and can easily use to cover any gap in distance
His illusions probably won't work here, since he can only project himself as a little boy, which the Alien can counter with its enhanced senses
Both are pretty skilled in stealth, but Jason himself isn't really used to being hunted, and when he has, he either falls into an ambush and muscles his way out. He is smart enough to leave traps around, and since this is a composite version, he probably still has his intelligence boost from Freddy, which allowed him to not only recognize a trap set up by federal agents, but also outsmart and sneak up on them.
Combine that with his enhanced senses, which includes hearing that can be boosted, he most likely can sense out the Aliens location, especially if it relies on echolocation. So he probably won't get ambushed too badly.
The acidic blood and spit may prove to be a problem, but with Jason's resistance to pain and regen, he should be able to overcome it.
If Jason does find himself on the losing side, he can always use his rage to give him an extra boost to power through.
And if worst comes to worst, Jason can just use his heart to hypnotize the Alien into letting him possess its body.
