The thing is, Rachel is actually the daughter of the Phoenix Force. Jean Grey is an avatar of the PF. Big difference. In the future Rachel came from Jean was replaced by the PF who did the usual replace Jean, let Jean heal at the bottom of a lake, then hook up with Scott in Jean's place thing. Except in that future, Jean never woke up. So the PF acting as Jean eventually had a child, Rachel.
Then the mutant registration and sentinel stuff happened with lots of screaming and dying. Sad stuff.
While Rachel herself has yet to show signs of developing her own Phoenix powers, she will. Its been established many times that Rachel is a unique entity in the entire marvel mythos, like her mom.
Jean achieving White Crown is supposed to mean that she has merged with the Phoenix Force and can now use its full powers. ummmm yeah. Its a bit of a retcon by a writer to try and set Jean above and beyond all the other PF users. It pretty much means nothing in all honesty. The next writer down the road can take and name Hope Summers the Purple Phoenix of the Scepter and have it be just a valid.
So while Jean has the WPotC title, its really just a title. Nothing more. At no point in the past has Jean before that ever come forward and said she only had part of the PF powers.
All that being said, the PF is a multiversal entity with the ability to start or end entire universes. Rachel with the PF should have the same abilities. There's just no way Trigon can match that sort of power.
As someone who has rescued cats and has 4 currently, my advice would be not to look at the breed so much as the personality of the cat. All cats are complete individuals. Yes, some breeds tend to have certain characteristics, but they tend to deviate much more than dogs do.
I would also recommend going to a shelter to find your roommate. Yes I said roommate. Because lets be honest, dogs have owners, cats have staff. Its true. If you are afraid that you new roommate will be lonely while you're gone running around, I actually suggest getting a pair. Shelters try to adopt them as pairs all the time especially when they happen to be siblings, and no having two cats is not double the work. Cats from shelters also tend to be extra snuggly. Maybe they're thankful for being brought home, or it could be my imagination. Other people have noticed the same thing though.
However, keep in mind that most cats shed. Plus, you will more than likely need to train them not to claw the couch. Also I recommend scoping the liter box once a day and changing it completely once a week to keep the smell down. You will get used to the smell, but guests will pick up on it pretty easily. Finally, if you do bring home a cat(s), try not to change their food too much. Cats really are creatures of habit. They love routine and changing stuff up around them tends to upset them and their system.