Kevlar, kevlar, kevlar.
Sintered work and last, but in the alps they’ll be squealing like hell with the long runs and will overheat quick.
Organic is good, but you’ll go through those fast and remember it can rain in the alps in the summer. They’ll be destroyed in a day in the wet. In fact I destroyed kevlars last year in two days in Morzine, but one of those days was biblical level of rain and mud. Went through to the backing plate. Wasn’t squealing much though, but the sintered guys were making a hell of a racket.
And +1 for Superstar kevlar. Their sintered may not be amazing, but the kevlar are great, and you can get 4 for the price of one set of original branded pads.