You have some really good points here. Some big chunks of information. I get the feeling that Rosenburg's pitch isn't a retelling of classic Phoenix stories, but something fresh. Mention of it being a character study is music to my ears as its important that we get inside Jean's head as she comes back all these years later.
The Jean Grey solo series is slightly odd with the Jean Grey ghost figure, which seems a little OOC and doesn't really make sense as Jean is one with the Phoenix and therefore couldn't really be a spirit? Maybe it's actually a fragment/imprint of the Phoenix? This'll be resolved in #11 I suppose, with the conclusion of Psych war.
Kitty & Beast having large roles is unexpected as they're not the first characters I think of in relation to Jean. Ororo has the closest ties in my opinion, and I'd like Iceman and Angel (the older incarnations) to be impacted as the remaining members of the original X-Men; the first class. The rest of the Greys (Rachel, Cable, X-Man) ought to feature and I'm hoping for tender moments once the conflict is resolved. I'm sure Jean will have a lot to say to Hank, Bobby, and Warren given all they've done and been through in her absence.
I have no problems with a new Phoenix look. I personally want something in black & gold. Even the classic suit with a recolor could be enough of a creative difference to signify something new. I doubt there will be anything too radical as they wouldn't want to lose the essence of the character, but I have no problems with an updated aesthetic.
Wolverine with an Infinity Stone still has me so confused. How that comes into play, either here or in another series is puzzling. I guess it has something to do with the Final Host and therefore the BC Avengers. Also worth mentioning is that young Jean Grey was the one to discover that Logan had escaped from his adamantium tomb. I feel like Jean/the Phoenix may have something to do with his return.
Xavier's return is another curious one. He doesn't have a body for starters, and his role in the MU is questionable. His students have outgrown him and I would argue that the current generation of mutants would view him as outdated as the times have changed. Furthermore, Xavier was never really their teacher or mentor, that role went to Cyclops, Wolverine, Storm etc.
I think Magnetos attempt to send the O5 back to their own time will first result in the cross-time capers storyline in X-Men Blue, possibly due to some malfunction or miscalculation.