AFAIK you can’t pick a channel manually. Also, channel 18 is not a great choice, as not all Zigbee devices will work properly when the channel is not one of 11, 15, 20 or 25.
The Hue hub is not part of your Homey Zigbee network, it maintains its own (completely separate) network. And AFAIK the ATV doesn’t support Zigbee at all.
