For her skin: I believe Beyonce has 'Keratosis Pilaris' a skin condition that affects 40% of adults worldwide. Here's a link:
http://dermnetnz.org/acne/keratosis-pilaris.html
For her dry, cracked feeet: forget moisturizers, she can also pay a visit to the pedicurist. God knows how much money girlfriend has.
For her shoes: they seem to have some dusting on them, perhaps that's why her feet look a little 'dusty' as well?