Yes the bios is a 16 bit program on all architectures . Basic input output system is what those letters stand for
Yes the BIOS api is also a standard that all architectures follow. It allows you to talk with bios routines and have them work flawlessly on other machines with different biases. They share the same interface.
Many bioses however have been know to have bugs. Something to keep in mind if working outside of an emulated environment