I've said this before and I could get shit for it, but IMO filming skiing with a 50mm just doesn't work. It's too cropped. I love the lens for shooting short films and for shooting portraiture but it's more limiting on the hill as it is helpful. Plus the 1.8 or higher aperture isn't that wonderful because you can't get good use of it unless you have an ND filter.
IMO if you're into getting stylistic shots and aren't looking for the "hood crew" look, a fisheye is a poor misallocation of funding. For a zoom, the Canon 70-200 series is great, but you can get by until you're more experienced with something like the 55-250. It's a shit lens, just like the 18-55, but you can make it work.
OP, the Tamron and Tokina work wonderfully together, I'd recommend shooting 60-70% with the Tamron and 30-40% with the Tokina.