@TLane 

First let me state I have not used any of these devices nor Centery Link.

I looked up that modem and it is what is called a gateway which is both a router and modem. Most Gateways have a mode called "bridge mode" which can be set to bypass the modem part of the gateway. Then you attach the router to the gateway with an ethernet cable to set up your network. That is the only ethernet cable to the gateway.

other ethernet connections will be to the modem. The modem will also control the wifi.

Mesh systems require all mesh units to work with the same mesh systems. Different manufactures and some models do not work together. 
 

If it were me, I would not get a Gateway if I was going to just bypass it. Just get an approved  modem to attach to the router. I have Xfinity and use an Xfinity approved modem and attached my router to it. With Xfinity, I can change modems without calling them but there is a process that needs to be followed. The ISP needs to know what modem they are connecting to.