The child did well. I do worry. I am a survivor of a helicopter crash. I have a new respect for our profession. Critical care transport experience on ground ambulance or fixed wing team.
Specific requirements vary from program to program.
In terms of experience, more is better. Getting as broad a base as possible will make you far more attractive as a candidate, rather than knowing every detail in the world about one particular sub-specialty area. All these course and certificates are nationally known and offered by a variety of providers. The certification exams are given by their governing bodies, and the exams offered once or twice a year. The program that hires you will be responsible for training you to function in this unique environment.