I have a Netgear AC1600 router. I want to switch to Verizon Fios for internet only and will connect everything though Wifi. I keep finding conflicting info online if this is all I need.

What conflict?

There really isn't a "modem" with FIOS.

They mount a box IIRC that is near or next to your telephone interface box and the network cable from that goes to whatever router/switch you use.

Depending on what setup you go with from them, the supplied FIOS router is also your wireless hub. It serves both purposes and also handles all the on demand features of the service. Unless you have a fairly large house or a lot of thick walls, the WiFi has pretty good range and works reasonably well. I wanted mine to reach out to the backend of my property so attached a netgear wireless hub to the router and use it as a network extender and that will work too if you want or need to go that route.