Reality warpers + Jakeem thunder, Superman, and Spectre are excluded.
I'd guess Bishop, Spectrum existing as energy, and Darwin can probably counter transmuting from Firestorm. Other than that the fight can probably go either way. Speed is even with spectrum and black racer being (exactly light-speed?). Not sure if Black Racer is really a superhero, but outside of him I don't know anyone as fast as Spectrum on Dc. Basically, he's included to prevent speed blitz. Beyond speed, Marvel composite maybe has more raw durability and magic powers (Blue Marvel, Vision?, Black Panther's suit, and Brother Voodoo). Whereas Dc composite maybe has better defense (auto-shields +always intangible- John, Crimson Avenger) along with multiple energy manipulation types (Vixen, Static Shock, Black Lighting, etc). Dimensional manipulation wise, I figure Cloak's teleporting can deal with Cyborg's boom-tube stuff.
Scenario 2: Both sides get prep-time.
Combo Nu and Pre-NU...