I totally get why they are playing (I'm less convinced that any of them are useful on the wing). But, part of why they are playing right now is our schedule. Against top sides, it still has to be Kovacic and Kante, IMO. Against parked busses, I'd go with Barkley and Kovacic right now. Somewhere in the middle is the Barkley + Kante pairing.
We'll see what RLC's defensive contribution is like by the end of the season, but as of now, having these 4 makes our midfield very versatile. Cesc may well be gone next summer, so we're looking at these 4 plus Jorginho to take up the 3 starting positions and 2 bench spots which is great, IMO.