What I found noteworthy in the video you linked to of the scene where Deadpool's costume is slowly taking shape, is the fact that right after Wade Wilson asks the audience
Is the mask muffling my voice?
he changes the material, from something nylon-like to something sturdier, which looks like carbon fiber. Since carbon fiber has high stiffness, and can ...
I don't think there's an in-universe answer. You're looking for realism in a character that is unrealistic on purpose - not only the super power but the way he breaks the 4th wall.
They made it on purpose for the movie so the character would be more expressive. You can watch the FX artist talking about it here.
Characters making the costume themselves is a ...
The Phoenix of legend is a bird that is born from the ashes of either itself or its parent. It has long been associated with resurrection and rebirth.
The Phoenix Force is so named (both in and out of universe) because it resurrected Jean Grey. It also usually manifests as a fiery bird.