Stranger and krona (im assuming this isn't the most recent incarnation of krona judging from the pictures) are abstracts so their power alone can rival that of a well fed galactus (though im not sure about the stranger but seeing how he could have potentially been the fourth face of the living tribunal alongside galactus, eternity and death im assuming he's close to them in terms of power), Krona and brainiac are the best in terms of being scientists here imo. Don't know about egg fu and thrann but the ones i mentioned alone would win imo.
Scientists. We've never seen a fully fed Galactus but he has been beaten before by lesser beings and giving the scientists a century of prep is a long time. If reed could do something to repel or heal Galactus in a short time, I'm pretty sure the scientists could think of something in a year.