Does this only compress your height?
After 1000 sneezes you'll be 36.77% of your original height. You'd start becoming very oddly-shaped if it didn't shrink all your dimensions.
Do the WYR Pixies magically make it possible for your body to function at extremely small sizes?

Your body stays at the same proportions and yes, the WYR pixies make you able to survive at tiny sizes.

I put waaay too much thought into this question. Thank you excel... >.>

...UNFORTUNATELY I suffer from "snatiation", which is what the multiple sneezing is called. My kids get a kick out of counting and wagering on the total.My average is between 25~30, and, while they find it amusing, I am positive that's how I'm going to die, as its hard to catch my breath after a sneeze jag...