Have you ridden both the flagsip and highlife?
If so, what are the main differences?
Yes. I only comment on boards I've ridden at least a full day and if on other boards, I'll give the reference. I own a Flag, was my one quiver board in '13, in use about 40days. Did demo the Highlife for a day when looking for a board to complement but decided against it cos it's too similar to the Flag on groomers (and just by the shape of it it was clear that it won't be close as good in pow). Both stiff n stable n fast transition/response, both fun to go straight n carve, both bitchy in moguls. But Flag has so much more rocker in the nose, so technically the same size would have less effective edge (which I didn't recognize as my weight is too low to actually overstrain that edge), but if you usually choose boards sizes to just fit your weight in the range middle, I could imagine that the same size of both boards could feel different. Anyway: The Flag is a big mountain board that can
be ridden on groomers, but it really shines in BC. OTOH, the Highlife's an all mountain board that can
tackle some fresh but not optimal in deep. BTW: Read the link
Floppy at speed? Well, I promise
the Flag will be stable at speeds faster you mentioned and way faster than I'd ever dare to even think to consider. Got some speed freaks in my pack... after trying my "small" Flag, SO ordered a bigger Carbon Flag (main purpose of it is BC). He also tried the XV, but as we hardly ever ride frozen waterfalls, its extreme magne seemed unnecessary - with the disadvatage that it digs while carving on groomers. As you seem to ride icy slopes frequently, it could be an advantage for you tho. Buddy is the same point it straight rider - mainly resort riding, only occasionally hitting sidecountry - and swears by the Coal (and yes, I did ride that Coal as well and can confirm that it's fast n stable).
All in all: The boards in your list will all be fast n stable and can handle pow, same same but different.
Guess, it's more a question of what's your main
aim. Optimize on groomers or optimize on pow? If the second, look for something with big rocker nose as XV or Flag; if the first, go more in the direction of Coal or Highlife (less rocker nose, more pronounced camber).