Can you use Yaz (drospirenone and ethinyl estradiol) birth control pills as emergency contraception?

Yes. There are a number of options for emergency birth control including dedicated meds that are available over the counter, dedicated prescription medicine, and use of high dose regular birth control. For information of how to use regular bc as emergency bc, see http://www.Not-2-late.Com . If you need ec, you should consider using regular bc such as iuds and implants. The most effective and easy!
No. Officially no. However, used in certain concentrations it could be helpful. Plan b is one of two fda approved methods for emergency contraception. It is also over the counter.