Job work related

Hi greetings...
I have a query regarding job work..
I will give raw materials to the job worker,
He will finish up the goods and give me back.
In this case ,
1)job worker is not registred(turn over will be below 5 laks)
2.he don't work only for single person. Will work for the principals who ever give him work.
My queries are
A.Is it necessary to add job worker place as additonal place of business?
B.more than one people can add same job worker place as thier additonal place of business ?
C.im sending job worker with delivery chalan without paying tax.
But he retuns goods which are lesser worth that sent amount.
(how to deal this)
D.an unregistred job worker can send my goods to another unregistred job worker?
E.reverse charge mechanism i need to rise purchase invoice ? Or any separate invoice?