Do a subforum search for “multiple my cloud remote access” and you’ll get several hits for past discussions on remote access issues with multiple My Cloud’s. Here are a couple of those past threads:
https://community.wd.com/t/multiple-myclouds/173045/
https://community.wd.com/t/remote-access-to-multiple-myclouds/96835/
https://community.wd.com/t/multiple-my-clouds-on-same-home-network/164926/
On the port number question leave one My Cloud using the default ports of 80 and 443, then try configuring the other My Cloud using alternate port numbers like for example; 8080 and 4443. One would then configure four port forwarding entries in their router to point to the first and second My Cloud’s IP address based on the port numbers.
