This is what happens when you don't have a locally based aircraft. Easyjet will always cancel the flight if there is any risk of fog/snow/ice/high wind to minimise diversions and any disruption to subsequent flights.
If you think two nights in a row is bad, just wait until the winter start properly. I can see the caledonian sleeper being quite busy come January.
Oh, and in all my time at INV, KSS has never been a specified alternate, always ABZ.