After 1.5 hrs of experimenting...
It wasn't easy to decide on what body shape my character should have. Through an "intuitive approach" of shifting anatomical proportions, it was still decided to remain on an avian's concept instead of a wyvern's. Wyvern can be kept to the wyvern... The phoenix needs something more like an bird's, after all.
p.s: I also have to remember to keep the neck shorter...