Just to clear things up
-Can they recall loan players?
Yes. Real Madrid and Atlético can call back players who are away on loan, as long as no money changes hands between the two clubs involved.
-Despite not being able to register anyone, can they still sell players?
Yes, the ban does not stop Real Madrid or Atlético from offloading players.
-Does the ban affect club coaches?
No, coaches are not included in the FIFA transfer ban. In other words, Real Madrid and Atlético can change coaches if they want to.
-Can they bring players through from their respective B teams?
Yes, the FIFA ban does not stop the two clubs from bringing players through the ranks to strengthen their first teams.