Just letting you know this is a bit of a silly thread when you use a character like white crown phoenix who is basically the actual phoenix who is fairly well established in the cosmic Hierarchy so asking who could beat WCP is a fairly short and known list and as such a moot question. Also you're given examples do squat to WCP.
To answer you're other question as to a regular phoenix Jean
most reality warpers with a fair amount of control. High level mages. Hourman w/ Worlogog. Black Alice, Spectre, Many Higher level demons, Thanos as the avatar of death stands a very good chance as well.
Dr. Doom would punk her given prep as would Reed Richards, and Hanky Pym.
Loebforce Rulk could do it. Surfer and Thor might not pull majority but I can see it happening.
Your average reality warper is not going to cut it. Nor will many high level demons. Beings only in the herald level range such as Surfer and Thor have no chance.
Perhaps I should have been more specific. By High end Demons I mean the likes of Zom and such. In terms of Mages Nabu, Sise-Neg etc. Also I think a high end thor and surfer might pull a win or two out of a hundred. By no means do I think they stand anything resembling a chance of a majority. Most reality warpers lack control. I think some like Absolom Mercator/Mad Jim Jaspers/ Franklin Richards/ Jamie Braddock could pull it off.
Yeah fair enuff mate but isnt the one above all not the celestial one the actual God in the marvel universe well beyond WCP... Also didnt XORN do something with an EMP to defeat the phoenix??