VinnieFI think Mike Wilson had some of the first double corks. Not sure what
movie but when he's hitting that pipe gap thing I think he does one
The first "cool" double flip was probably the kang flip by Jon Olsen. First double cork? Tough to say but definitely Wilson could be a contender. The one you're talking about was an MSP movie... A lot of different double combos were done in the 70s through aerials. When this came out, a lot of old school (at the time) dudes were doing dub flips and fucking sending it. They were gnarly but not exactly getting a lot of love for it. A big portion of the "core" community was into seeing things like urban skiing, unnatural spins, innovative grabs, and style over big gaps over things that were more relatable to aerials or anything influenced by FIS. In this era, the schrabs and others were really thrown under the bus for doing doubles,
At this time, "newschool" skiing was more interested in what people like JF Cusson, Tanner Hall, Pep Fujas, and Dave Crichton were doing. It's not to say sending big ol' doubles and big gaps wasn't important or appreciated but at the time people were doing things that actually hadn't been done on skis before. Tanner's Dspin 10 a year later caused a bigger fuss than than any trick in this movie. A perfect storm of Kris Ostness film-making and at the time "cool" skiing came a few years later with Teddy Bear Crisis.