The HG612's default IP address is 192.168.1.1, so it should be fine with a router that is using 192.168.100
My HG612 is still using 192.168.1.1 & my Netgear router is using 192.168.1.254
With the HG612's LAN2 port connected to a spare router port, I can indeed access the stats wirelessly & via a PC connected to the Netgear by cable.
Once unlocked & set up that way, all PCs accessing its stats can have dynamically allocated IP addresses as they communicate with the router.
I don't know how to disable the LEDs via telnet.