Concerning Does a big nose help you sing better?:
One thing we learned in high school chorus (besides “don’t sing with gum in your mouth”) was that part of what makes operatic sopranos such tremendous singers is their huge cheekbones and big sets of teeth (i.e. a really big resonating cavity in their mouths), both of which contribute tremendously to the amount of “head voice” they can produce. If you look at photos of opera singers like Rosa Ponselle and Kirsten Flagstad, even Beverly Sills, they all have these huge high cheekbones and lots of teeth.
Streisand, of course, also has this configuration. It’s not just her nose that’s big.
Whitney Houston has big teeth, but not particularly high cheekbones, and kind of a button nose, and I notice that most of her sound seems to come off her larynx.