You are going to only have one 4K source; your UHD Blu Ray player. Optical out from the TV and assign the audio source to the input selection?
Any other 4K will be app based from the TV and UHD player. TV HDMI 1 is the receiver HDMI out for all your 1080 and TV HDMI 2 is UHD player direct.
But as per the above post, wait 5 months for the 2016 lineup. Go with one of those or get a 2015 on run out. Win/Win