Don't all

 Speak at once 

Is that musty person

 Living in the vent 

Do yall

 Live in the wall 

Yall all should be spic and span

 Clean  right now 

Every time I'm in the bathroom

You and your children making lots of noise behind the wall 

Don't play in the bathroom

 Take a bath you and your children 

Do you have the capacity

 Are you unique