3rd party router and different scenarios. Please help

Hi

I am an ATT uverse customer. I am now considering buying a 3rd party router; basically i really need to buy a good range (MOST IMPORTANT), dual band WAP with LAN ports and USB (print/file server), and I have been looking at the netgear nighthawk R7000. This is sold as a router/wap, so i could take advantage of the better capabilities of this router as compared to the router included in the RG (I have to check the mode but i think that mine is the NVG589).

Current:

RG: Modem / Router / WAP / switch / Coax connection to main TV box (DVR)

I have some ideas (please forgive me if some do not make sense):

SCENARIO 1

RG: modem / switch / Coax connection to main TV box (DVR)

new device: Router / WAP / switch (connecting to other TVs by CAT5)

In this scenario possible at all (RG in bridge mode). Would i be able to use the LAN ports in the RG then (I dont think so)? If this was possible, being the new device a router/WAP, would the coax connection to the tv box/DVR in the living room still work? I live in a rental property and that is the only available cabling from the RG to the living room; The other TV box (s) luckily is (are) connected using CAT5. Would I be able to share the DVD recordings between all the TVs?

IDEA 2:

RG: Modem / router / switch / Coax connection to main TV box (DVR)

new device: router / WAP / switch (connecting to other TVs by CAT5)

If this one possible ("router behind router") for this RG? Would I still take advantage of the better capabilities [as a router] of the new device without any interference (lag) caused by the RG router? 

Thanks for your help

PS: I am a computer programmer but as you can see my knewledge of networks is very limited