How/if can I get the contact who created order (for a company), from Sales Order or RA. Like there is a company ABC, and it has contacts X,Y,Z. Now if How will I know which contact created the order (X,Y,Z). I have to send back email to him. I thought the email on SO/RA belongs to contact but its not happening in all cases.

Create a custom transaction body field for custbody_customer_contact. I don't think there is a standard field for that.

I also didn't find something. Do you mean create custom field to enable that on webstore and get the value while order creation.