@jliolios Got it, got it. Alright, this all makes much more sense now.
Foundational understandings:
1.) When you assign pfSense's GUI (called the webConfigurator) a port, it listens on all interfaces, including both WAN and LAN. Since most people never 'open' this port to inbound connections on the WAN interface, it typically never presents a conflict or a problem that the webConfigurator's nginx-based web server listens on all interfaces by default. (See this post for a recent thread on this point.)
2.) You have both:
'Opened' port 9443 on the WAN interface; and
Crafted a NAT rule to forward any/all inbound 9443-destined traffic arriving on the WAN interface, to be 'redirected' to the EZProxy host that I'm assuming is not homed to 172.16.0.1
3.) At some later point, you changed the webConfigurator's listening port to 9443. It would not have been readily apparent at that time that inbound 9443-destined traffic arriving on the WAN interface now had two potential and conflicting routes to take: the webConfigurator webserver, and the EZProxy LAN host.
With all that being said, and returning to your original question, what do you mean when you've said:
[in Use of a custom port for admin console caused issue with NAT using same port:]
in this case 443 took a back seat to 9443