Dunno about Sky, I use a freeview HD dongle in my laptop and watch on 360, media centre gets tv guide via web and puts it on xbox, channel changes, scheduling recordings, supported from 360.
So I would be very surprised if Freeview wasn't supported on XB1. It would be a step backwards if it didn't. MS has been supporting TV on xbox via media extender for quite a while. They may drop the media extender but supported tv receivers should still be supported. I have a Samsung freeview DVR, with HDMI CEC (anynet+) so it should work ok.