I’d put my money on Dream a.k.a. Morpheus. He’s the King of Dreams. He’d wipe the floor with Freddy.
Asked, and answered, in the OP.
How about Freddy vs. The Corinthian?
If you assume them to exist in the same universe, Freddy’s nothing but a trumped up Nightmare. Probably not even as powerful as the Corinthian, as he’s a specific terror that sprang out of reality, rather than an archetype (ignoring, for the moment Wes Craven’s New Nightmare, just going with the canon of the non-meta-movies.).
And Dream is supreme within his realm. Even Azazel, whose powers, unlike Freddy’s, exist independantly of the Dreaming, is subject to Dream’s whims within the Dreaming.
Freddy doesn’t stand a ghost of a chance vs Dream - or, for that matter, either incarnation of the Corinthian.
Freddy vs. the Corinthian might actually be fair. What does the darkness within humanity fear? Freddy vs. Dream? That’s like arranging a fight between a serial killer and the angel of death.
My brother asked me this question.
I started squeezing my thumb and forefinger together, but before I could answer:
“You’re imaging Morpheus getting really big and squishing Freddy, aren’t you?”
“Yeah, so was I.”