@MarineE7,

If you can let me know what your current equipment/network setup is, I can tell you how much more complicated it would be. From what I was looking at the main issue is that Verizon validates the authenticity of the mini boxes through their router and the fact that the router creates a hidden 5Ghz network for the minis to connect to. I can imagine that there is a method of running both networks separately through a managed switch using VLANs, but I can imagine that the best course of action would be to use the original router, in conjunction with your Deco.

You can set up the Decos in Access Point mode so that they will extend the coverage of the network created by the FiOS router. It appears as though Verizon makes it EXTREMELY difficult to use third-party routers with their One TV system. Therefore your best course of action is to find some way of extending the existing network, potentially through the Decos AP operation mode.