switching a cluster from iptables to firewalld while updating to 4.3 from 4.2

in regard to this solution:
https://access.redhat.com/solutions/4134201

we are in the process of updating a cluster from 4.2 to 4.3, manager has already been uploaded, now we need to update the hosts.
we also need to switch the firewall to firewalld, currently it's iptables in the cluster settings:

what is the correct order to do that?
1) update all the hosts from 4.2 to 4.3
2) set the cluster settings in the manger set the cluster firewall to firewalld
3) reinstall each host

is that the correct order to do this?