Hi Tami!
Those are some really great restaurant choices!
Chef Mickey's is a very popular choice and may I say delicious choice! The best part of dining at Chef Mickey's are the characters! It is difficult to give you the exact cost as prices vary depending on time of year. I had dinner there a few months ago and paid close to $50 per adult.
Biergarten Restaurant is probably one of my favorite restaurants. The food is amazing! What I love about it are the German dishes, particularly the carved pork, the potato dumplings and the pork schnitzel. Like Chef Mickey's, it is difficult to provide you with an exact price as these vary depending on season. During my last visit, I believe I paid close to $35 per adult. If you are considering visiting these dining locations, I would strongly recommend a dining plan.
It has been a pleasure assisting you Tami! If I can help you with any other planning need or question, please feel free to send them my way!
Thanks for sending your questions to the Disney Parks Moms Panel!
Yael