Parker can play wing or power forward...I don't think it's really fair to compare her to Griner or Fowles, as she hasn't really been a true center for a long time, including her college years. It's fair to compare her to EDD and Stewart and Charles.
I think she's tougher than EDD and a little more consistent shooter from 3. I don't think she has the power game EDD can show, but Parker is capable of that.
Compare her to Charles, and I think she has a more polished offensive game than her, including consistent 3 point shooting. Charles may have the better post up game, but Parker can get to the rim.
Compare her to Stewart, and I think her maturity and experience should count for something. Although, I will admit that in the long run, Stewart will probably be just as good as Parker, I don't think she's there yet. Parker has a better post game than Stewart, also, though many on this board may disagree.
Defensively, I think all four players are pretty equal. All can block shots and guard.
I think Parker is undoubtedly the best passer of all of these players. Just look at her assist numbers over the past two years (granted, Nneka had an amazing 2016).
With that said, I find it very surprising Parker was left out, and I find it surprising Stewart was included. There's not doubt Stewart is a great player--but so is Candace, with similar skills, more experience, and just as good of a defensive player, with the added bonus of being an elite passer.