After adding "extraargs=net.ifnames=0" to /boot/armbianEnv.txt you should have both eth interfaces as eth0 and eth1. WAN becomes eth0 and unfortunately it is associated to the LAN port (LAN led) instead of the WAN one.
Other issue that has been mentioned here: Only the middle USB port works as USB 2.0, the other port doesn't work. Any luck with this issue anyone?
$ lsusb -t
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 5000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 480M