For non-electric cars, people in mainland Europe use litres/100km to describe fuel consumption. In the UK, we have historically used Miles per (imperial) gallon, although nowadays we buy our fuel in litres while still using miles on our speedometers - so neither of the common measures is actually useful! Most people still seem to talk in MPG, though car manufacturers often quote litre/100km as well.
For EVs, I was going to say that I'd never seen your "kWh/100km" metric anywhere, but a quick check shows that BMW does quote that in its EV specifications; however, Nissan quote Wh/km. Renault just say that their EVs have a fuel consumption of "0 MPG", while Volkswagen simply say "N/A" for their electric models. Citroen don't seem to say anything about consumption. CO2 (as grams/km) is widely quoted for both EVs and conventional cars, since it's important for tax purposes, but all EVs advertize zero g/km.
So Wh/mile and Wh/km are what Tesla report on the screen in the car, and there's no consensus to report anything else. In my opinion, these figures (Wh/mile or Wh/km depending on whether you are displaying everything else in miles or km) are the only important ones. You could display an MPGe figure for comparison to ICE cars; I don't personally like these much as they are extremely arbitrary, based on a lot of assumptions - but if you are doing so, then it wants to be MPG if the rest of the display shows miles, or litres/100km if the rest of the display shows km. Note also that this isn't a Europe/N.America difference - Model S in all markets has the km/miles configuration choice.
While we are talking about units, I haven't checked what you do with temperatures, but note that the C/F choice for temperatures is not locked to the miles/km choice for distance. Most (but not all) people in the UK will want miles + temperature in C.
(I haven't bought RemoteS yet, but plan to do so when 2.0 is available).
