Xfinity Xi5-P with Wifi Asus or Customer Own Wifi

I just traded in my older DVR and equipment to use the latest X1 equipment to take advantage of 4K and surround sound and brought home from the Xfinity store to self-install. What they did not inform me was that the Xfinity Xi5-P  even though wifi capable will not see a customer-owned wifi router.  Xfinity support simply said contact my wifi manufacturer Asus. Asus pretty much blew me off and said I would get a call back on the issue. Online search and Xfinity self-help have not given me any results. Before I start drilling holes to hardwire, I want to verify the wifi options I might have. I'm asking again as there is still confusion on this forum as some people are getting it working with the customer own modem and some responses says only Xfinity Modem/Wifi. 

 

My equipment is the Asus NT66R WiFi Router (not bridged) and Arris SB8200 Cable Modem. 

 

Is there a list of support Wifi Customer Own routers that should work with Xfinity Xi5-P?

 

Can the Xfinity Xi5-P talk to the new X1 DVR Box somehow other than wifi or ethernet?

 

Is there still a coax supported X1 remote non-DVR set-top?

 

Thanks in advance. Rob