Adding a second router to fiber home network

[wireless]

I want to add a second modem/router on my existing home network to get wifi and a wired TV connection to a detached building. I have buried conduit and can run Cat6/Coaxial from the detached building to the house to terminate at the ONT (Alcatel-Lucent) or the existing router location. It will be much easier to run cable to the ONT rather than the existing router (would need to add a wall plate and extra visible wiring). It appears the ONT can only directly supply to one router but can I add a switch right after the ONT and run one port to the existing wall plate the router connects to and a second directly to the detached building (about 100' of cable).
Also is there any reason to run both Cat6 and Coaxial or should i just run the ethernet?


More...