As Mwenenzi said, your itinerary is nowhere near valid as it's not a Round The World one. What you have is a "fly from LHR to various places and back" itinerary. Moreover, the only flight to MRU is from LHR, so even combining CPT and MRU on a valid xONEx is impossible. And you can only cross the Atlantic once.

The stickies at the top of this forum will explain how RTWs work, but I suspect they're not going to be useful for your friend's travel plans.