Actually I don't really see how would that work.
The auto-magic UDP multicast discovery won't work, but you can statically configure list of reverse proxies in the AS/WildFly configuration ('proxies'). However, the reverse proxy connections to the backend servers are initiated by Apache/mod_cluster and since NAT masquerades the IP address it won't be able to route to those addresses. Neither if you configure static NAT/port forwarding, the AS/WildFly will advertise the address of the connector/listener which won't match the NAT's address.
For anyone reading this in future, [MODCLUSTER-318] make connector address user configurable - JBoss Issue Tracker would help here, allowing you to configure the address httpd contacts JBoss/Wildfly on.