Then the Phoenix Force created her. What is the difference, beyond utter semantics? She is intrinsically tied to it by her blood, by her nature, in a way that absolutely no one else is. Saying that she uses "outside help" is like saying Storm uses "outside help" when she controls the weather which is an outside force, or that Magneto needs "outside help" because he manipulates magnetism which is an outside force. Did Iceman the "creator" of ice and temperature? Did Nate Grey "create" the astral plane of which he is a master of? Did Wanda Maximoff "create" the chaos magic that she is tied to so irrevocably?
As for the sources:
Chris Claremont, throughout his entire career, has stated that the Phoenix is an aspect of Jean's own power. That's how the Phoenix started off, after all. At every possible opportunity -- especially within the past few years as the original coccoon recton has become obsolete -- he's been quick to tie the Phoenix intrinsically to Jean. He had the Watcher specifically state that the Phoenix is Jean. He had Rachel Grey specifically say "I'm not the Phoenix, my mom is."
Fabian Nicieza states, in X-Men Forever, that the Phoenix ("The Resurrection Force") is an evolutionary aspect that humanity will eventually reach, and specifically points to Jean as the forerunner and representative of this state. Nicieza, incidentally, was the very first writer to use the term "omega-class mutant," in this very same miniseries, and introduces Jean and Bobby as the first ever confirmed.
As we all know, Grant Morrison builds on that line of thought, firmly establishing the Phoenix as the representation of Jean Grey's omega class potential throughout New X-Men. What's interesting is that he shows the Phoenix Force having a separate voice than Jean, but housing the exact same power.
And, of course, he states that the the Phoenix is the ultimate mutation. Mutation. Not "separate cosmic force." Being the Phoenix is Jean's mutation. There. Canon.
And I suppose I don't even need to mention what Greg Pak did throughout Phoenix: Endsong, tying all of the loose ends together and fixing all the holes left by the original coccoon retcon. If there's a different way to interpret the phrase "I am you" that Jean says to the Force or "You and I are one" that the Force says to Jean, I'd like to hear it.
Oh hey, and I even forgot one writer. Joe Kelly had Jean displaying a flaming Phoenix effect during his late 90s run, and had Jean saying that this was her own power that she was tired of hiding for fear of others' reactions. Her own power. Real flames, real Phoenix effect. Years before Morrison confirmed the return of the Force. I mostly bring this up to shut up all the naysayers who keep saying, "Jean only made pink psychic Phoenixes without the Force in her, she wasn't capable of making the real Phoenix." No she didn't, and yes she was.
Again, that's my evidence. What's yours, beyond "I don't think that's the way it works and I don't like it"?
Oh, and I'm assuming that we're disregarding for the moment the fact that Franklin Richards has no powers right now.