"Anna brings such a wealth of experience and hunger for success to the court while Storm made an impact for the Mystics during the second half of the season and at the Super Club competition in Nelson," McAteer said.
"Michaela is certainly part of New Zealand's rising talent and a player to watch, while Phoenix was back to her best this year and brings yet another dynamic element to an impressive line-up."
The Mystics have signed a full roster of 10 for the 2018 season, but can opt to contract up to 12 players. With star shooter Maria Tutaia expected to take time-out to refresh physically and mentally following next year's Commonwealth Games, the Mystics are expected to name at least one more player in the mix.
At this point the only recognised midcourters in the Mystics line-up are Elisapeta Toeava and Samon Nathan, whose signing is set to be confirmed by the Mystics today.
The Mystics will have able cover in the wing defence position, will Harrison regularly filling the spot this season, while Sokolich-Beatson has also been used on the wing on occasion.
But there is no obvious back-up for Toeava and Nathan in the centre-wing attack positions.
The latest signings follow last month's announcement that shooters Tutaia, Bailey Mes and Tera-Maria Amani will return for another campaign alongside new-comer Jamie Hume.