We were in Epcot yesterday for DS's birthday. Get the button from Guest relations- it makes their day a lot of fun!
Just about every CMwished him a Happy Birthday, and joked around with him about it. One of them pulled him aside and told him that he had a phone call for him, and took him to one of the 'internal phone system' phones that the cast members use... on the other end, Goofy was on the line, wishing him a Happy Birthday. Throughout the day, many more CM's asked him if he had spoken to Goofy yet.
In China, at the Kidcot station, the CM wrote "Happy Birthday" on his mask in Chinese.
When we stopped for Mickey Bars at the ice cream cart, his was free. We only did counter service yesterday, so he didn't get a cupcake or anything, but he was thrilled with the extra attention that he got overall!