Close, but, not quite correct... Jean didn't want to die and the Phoenix Force wanted to experience physical life... They (Jean Grey and The Phoenix Force) made a deal, but the deal came with a price which was not clearly specified at the time. My guess is that in order to save Jean the Phoenix gave her a portion of it's cosmic power in exchange for Jean's human conciseness, it placed Jean in the cocoon to heal and it when on to live Jean's life as Jean.
Yet, teen Jean does have her adulter part's memories of said events and that's how I figure she is tapping in to this new power level -- she's tapping into something whether or not it the Phoenix Force has yet to be seen. In any event Jean mopped the floor with the majority of the Shi'ar including Gladitor single handily.That reborn version of Jean wouldn't have go through the DFS events. Again doesn't really change anything compared to the original "cocoon" version. She still wouldn't be that "entity" that destroyed a star or whatever. (Or the PF would have to have created the egg after it destroyed the star but before being taken away by the Shi'ra. In that case the new Jean would have the memory of the events. But she still would be a new entity. A kind of "child" of the Phoenix)
That's how I saw it originally.... But, this it is quite a different scenario, one without all of the confusing multiple retcons.Not sure it worth the efforts compared to the original "cocoon" version :
The PF makes a copy of Jean and put the original in statis before going to the stars.
Later the original wake-up and goes her life without the guilt of destroying a civilisation. (Even if Jean feel responsible when she learns what her "copy" did. Because it still was her in most way that count)
Then later the PF comes back to Jean and merge with her. (Instead of knocking her on the head, putting her in another cocoon and making another clone
In term of what post-cocoon Jean experienced or the responsability that can be attached to her for the PFS events, its amount to the same.