Could anyone please confirm whether Airport Express or Airport Extreme base station provides DNS64/NAT64 functionality?
Apple access points do not support DNS64/NAT64. Does your Mac Pro have a second Ethernet port (most do IIRC). If so, you can use one port for your uplink and then set up a MacNAT64 network on your other port. Your iOS devices can join the MacNAT64 network in one of two ways:
I use bridge mode all the time. My main work machine is a MacBook Pro and that accesses the Internet via Wi-Fi. When I want to put an iOS device on MacNAT64 I do the following:
Plug in my Apple Thunderbolt to Gigabit Ethernet Adapter adapter to get Ethernet
Connect an Ethernet cable from that to a ‘victim’ AirPort Express
Set that up in bridge mode
Use Internet Sharing to share my Mac’s Wi-Fi on to the Ethernet and thence on to the ‘victim’ Wi-Fi
Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"
[1] Modern iOS devices support Ethernet via a relatively easy user configuration option.