I tried everything in this thread and was never able to get the chromecast to work. While I was searching for a way to use a different router with Fios I discovered that it is pretty much impossible unless you are lucky and still have a functioning ethernet port on your ONT(optical network terminal). I did come across a way to use a different router with the Actiontec Fios router by turning the Actiontec into a network bridge.
http://www.dslreports.com/forum/r17679150-Howto-make-ActionTec-MI424WR-a-network-bridge
Then it was only a question of finding a router on the Chromecast compatibility list. Note that this will only work for you if you do not use a Verizon set top box for TV, I use the TV service but use devices with cable cards that donit require the MOCA coax connection to get the program guides. This might seem like a lot of trouble for a working Chromecast but I have also had other issues with devices/services in conflict with the Verizon provided router and have long wished I could use something else. I got an Asus router on sale and the wireless coverage in my house is a different world of good compared to the Actiontec.