COSMIC SUPERBEINGS:
Exiles Hyperion
Genis-Vell
Captain Mar-Vell
Gladiator
Quasar
Jack of Hearts
Silver Surfer
Firelord
Drax the Destroyer
Photon
Wonder Man
Fallen One
Sentry
Thor
Beta Ray Bill
Thunderstrike
Warbird
Superman
Supergirl
Power Girl
Captain Marvel (DC)
Hal Jordan GL
John Stewart GL
Sentinel Alan Scott
Kyle Rayner GL
Guy Gardner GL
Wonder Woman
(all DC characters are post-crisis unless stated otherwise, all Marvel and DC characters are at normal power levels unless stated otherwise, all Marvel characters have their standard weapons, but no gems or powerups unless stated otherwise)
well i thought the cosmic superbeings would win cuz both Exiles Hyperion and Sentry have been stated to be able to beat Galactus, and Galactus is the most powerful one there so i figured the cosmics would win.
Full power was from my point of view turned into the assumption that
Full power Onslaught = a single Celestial based on the fact that Franklin Richards was stated to be equal to one, and it coupled with Nate Grey, Professor X and Magneto would make Onslaught > a Celestial.
I'm not saying I agree because Onslaught never showed anything that would place him near that levels of power, but working from that assumption that the above mentioned theory is valid then Yes Onslaught will Solo as well imo.