Newbridge is only for Lothian Motorcoaches so it'd either be Livingston or Longstone. I'd also like to see the 20 and 63 return to Lothian, as they make more sense geographically as part of the Lothian network and Lothian has always provided a high quality service. The 63 especially needs a new operator as it's currently very unreliable.
On the topic of the 40/X40 - how busy are these routes? I've caught the X40 once between Hermiston and the Infirmary and there was only one other passenger who got off in Gilmerton. I feel the X40 should be cut completely as it hardly serves anywhere of note, especially compared to the 40. Is there really demand for an express service between Livingston, Dedridge, Wilkieston, Hermiston, Gilmerton and the Infirmary? Of course, subsidised services don't always have to be busy if they provide a valuable link, however the 40 already provides the connection between ERI and Livingston, albeit more slowly. In my opinion the X40 is a waste of money and resources - the subsidy provided could be used elsewhere to provide a more useful service to places such as Eliburn and Deans South.