change node author with rules. using an array of users with specific role
Enable Views Bulk Operations


Create a view (Table format is the easiest to manage.)
Add a relationship Content: Author (not required)
Add the author field so you can see who is the current author 
Add the field Bulk operations: Content
Under Selected Bulk operations choose Change the author of the content. 
Save the view.


Now on the view page you will see a table of all your nodes. 


Check the select box next to the rows you need to update the author of.
Under Operations at the top of your view, choose change the author of content.
Hit Execute
On the next page, choose the user and hit next
on the next page hit confirm. 
Repeat / Integrate with rules...