adverbs - Meaning and the position of "all" in a sentence

1. 
   

   All my friends answered my questions in the class yesterday. Every one of my friends answered my questions...

   
   


2. 
   

   My friends all answered my questions in the class yesterday. Each one answered my questions...

   
   
   


3. 
   

   My friends answered all my questions in the class yesterday. Every one of my questions was answered by my friends...

   
   


4. 
   

   My friends answered my questions all in the class yesterday. Not acceptable English.

   
   


5. 
   

   My friends answered my questions in the class all yesterday. My friends answered my questions all day, yesterday.

   
   

Do you agree with these? I am confused with the fourth one.