Defaults to F though even though it knows where the user is located - for pretty much anywhere outside of the US I would think the default should be C.
[Mind you - it does remember your choice - so its not that bad]
Yes but it doesn't switch miles to km, only temperatures.
It doesn't look like this toggle exists on the mobile app.
In the web app, it's in the slide-right navigation. At the base, it looks like a speedometer toggle.