We did Chef Mickey 3 years ago before we moved her and my friend had told them it was DDs birthday (1 week late) and her niece's birthday - at that time they were given a placemat signed by the characters, and some sort of goodie with a candle...
I was at Crystal Palace Wed evening for my birthday, and when we went to our table there was a paper streamer and Mickey Head confetti on the table. At the end of the meal I was brought a cup cake with candle, and two of the CMs sang to me along with my DD. I was also given a birthday card signed by the characters. I had my birthday button on, and it is amazing how the CMs see those things - they must really keep an eye out, I had so many so Happy Birthday, and the characters pointed it out as well when DD was getting autographs and pictures. What a magical way to spend my birthday...... even as a grown up - it made me feel special, this was the first birthday in the three that we have lived her, that I was able to spend at WDW.
Okay - back character meals.
At Ohana's character breakfast on Saturday (this was supposed to be my birthday meal, until I decided I wanted to go out on Wed too) I was given a lei and a card when I entered the restaurant, and brought a really yummy choc chip muffin w/candle.
You can order other cakes for birthdays - I believe they have small round cakes available upon request when you arrive (around $13), and larger cakes can be ordered by calling the restaurant bakery (you get the numbers from Disney Dining), and I was told they only need 48 hours notice for these.
That's all I know about birthdays - we are having DDs birthday at 1900 Park Fare next Sunday (3/5), with 5 people, so I think I will be ordering some special cake, I have to call this week!