Everything runs through the router correct?
No. Guide data and VOD run through the router. Linear channels are delivered over coax and do not go through the router.
So if you're having picture freezes on linear channels, it's not a router problem.
Should I get the new Actiontec for $100 or is there another one Fios will give me for free?
I'd try calling VZ and telling them the wireless doesn't work on the router. They should ship you a replacement router for free. Guaranteed it will be newer than the rev. C and in all probability it will be the rev I which is the one they're selling for $99.
Verizon will give you whatever is in stock at the time. The store should be able to perform the swap for you, but if you also call Verizon they will usually overnight ship a new router to you. In my area, Rev. I routers have been shipping as the most common unit, inuding to users of the 15Mbps plan. Some Rev. F ActionTecs are being shipped still, but that is about it.
Chances are good you will get a Rev. I.