Kathy,
No,
Mickey's BBQ is not too loud. It is just another great Character meal experience for your kids! The great thing is that you are outdoors, so you get a totally unique experience, and one that can let you get further distance from the noise if it is a bit too loud for you and yours!
An important tip I have for friends when recommending this experience. Make sure you have at least one other Mickey dining experience in your plans. Since it is only held two days a week, and is obviously vulnerable to the weather, you should make sure you have one other experience that is a bit more 'reliable' in your week, just in case.
One of my other favorites is
Chef Mickey's, but you might also like the Playhouse Disney characters at
Hollywood and Vine at Hollywood Studios.
I hope that this helps!
If you have more questions, please feel free to ask me directly from my bio page!
Have a magical (and delicious) vacation!