OK that's interesting. They seem to be using the terms the opposite way around to other routers.
So what they're calling "Exposed Host (DMZ)" would usually be called "IP Passthrough". This is very similar to a Bridge Mode.
It's still not clear exactly what "Static NAT" is doing. It sounds like what most routers would call DMZ. I would be tempted to leave this disabled, especially if you have "Exposed Host (DMZ)" enabled.