The Phoenix Five are the result of the interference of Iron Man and the Avengers trying to destroy the Phoenix force. (This would be the same as if an ant had decided it wanted to destroy the sun.) The Phoenix Force has incalculable power and is only bounded by the capabilities of the host it is inhabiting. The Phoenix Force is a primal force of Life in the Marvel Universe and when embodied by Jean Grey, equated alongside the most powerful beings in the Marvel Universe including Death, Infinity, and Galactus.
The Phoenix-hosting X-men, called the "Phoenix Five. The Sub-mariner, The White Queen, Cyclops, Magik and Colossus."
I mention this because this would explain the current portrayal of the X-men who have become hosts simply doing what they already do, only bigger because the Phoenix Force first begins by using and magnifying the powers of its host.
It has a preference for Omega-Class entities like Jean Grey because it has a far greater capacity to utilize its amazing powers. It also considers Jean Grey its ultimate host and through her has manifested its most powerful form, the White Phoenix of the Crown.
Think of a host like a fuse. That host can only channel as much power as they are able to, so the greater their innate ability, the greater the potential output of the Phoenix Force.
Ultimately, as the Phoenix spends time in these hosts, it will begin to manipulate greater potentials of its natural abilities, giving each of them the potential to alter reality as they see fit.
Given the powers of the White Queen, and her having been a host before (though the Phoenix might not remember her) and the innate bias of the Phoenix Force as a psychic power, it will probably find her the most compatible of hosts, followed by Magik whose mastery of magic will resemble the Phoenix's powers most closely. Expanding the ranges of powers for Cyclops will probably mean his energy projection (and absorption) powers will be even further increased. The Sub-Mariner and Colossus should become all but physically invulnerable.
Eventually, they should all be able to manifest a variety of the Phoenix's innate abilities which include but are not limited to:
the ability to manipulate cosmic energies and to tap into the life-force reserved for future generations, thus denying them existence.
The ability to project its cosmic energy as beams of immense destructive force.
the ability to transmigrate throughout time and space and is capable of spaceflight.
The ability to directly absorb physical energy such as Cyclops' optic blasts or even the entire energy of a sun. (It has done so in the past, destroying an entire civilization.)
the ability to directly absorb the energy and life-force from a foe.
Since it is the nexus of all psionic energy, it has mental abilities of cosmic scope, including telepathy and telekinesis.
The ability to return the dead to life or resurrect itself after death.
the ability to alter reality, rewriting history, making permanent changes to the space-time continuum and anything within it including the altering of metahuman potential and abilities.
Jean Grey as the White Phoenix, the most powerful manifestation of the Phoenix in the Marvel Universe, Earth-616.