There's more akin to Assault Rams than Storm Talons so I'd honestly suggest Skimmers not AC.
They're a wee bit OTT for Epic as well (40k is basically a giant case of power creep) so using the stats without modification, taking every possible weapon and making it a separate shooting attack, and lastly including options for EVERY possible weapon configuration is generally discouraged. I'd suggest taking the iconic load out and starting there.
I'm not going to cover this one here but AA is also bound up with a set of conventions that shorten ranges as a starting point for obvious reasons.
Let's look at the Stormfang first. It's pretty obvious the Helfrost cannon is iconic so let's have that included. I mean if you're not bringing that, then why bother? AMIRITE or AMIRITE?
However flying uber TK shooty flyers like this are pretty much silly talk. I mean even the most advanced race in 40k, Necrons, don't have something this powerful and even then, it's been a bitch to not be complete poppycock in EA for the Experimental Newcrons list.Now we've got an option for some one-off support missiles, an up close MM attack, or the heavy bolters for use. So choosing between them it's important to figure out the "typical" reason and tactics of this unit in play. That is, why does this exist in the larger FoC of the Space Wolves (and not amazingly some successors again as of the new Primaris!
) It's obvious that we can see that the major role this plays in a puppies is a heavy support vehicle even if happens to be built from pure solid handwavium and one shot insta-gibs entire fleets of helldrakes in dogfights while pumping out The Trooper by Iron Maiden at max decibels... So with that in mind, it's pretty obvious when coupled with the existing Approved Space Wolves list we're talking skimmer that wants to lay down some hurt while allowing those big groups of hairy brutes to get into assault range. While we've fine to use any of those above secondary weapons some are better than the others.The MM are nice weapons but short range and better suited for the complementary transport unit, the Stormwolf, which wants to be an assault transport and wreck face. Likewise the missiles are good but come with extra book keeping and are more of a Opportunity Fire style weapon and don't actually bring an ability the puppies need really. So that being said I'd pick the Lascannon over the others as AT fire is a bit more important for Marines. BTW good choice on it being considered twin linked and FxF.
We could add in the additional bolters but then you're going to need a pretty good price tag for all that. Going the other way, I'd make them instead small arms and bump the FF of the unit, after all they're really there for killing things that get up and close vs the type of long range sustained shooting epic ranged attacks represent from the "real world", as much as that can be said about a game that involves chainsaw swords and hulk smash gloves being primary weapons! We can argue the same in tactical application of the missiles in that they'd probably pop one or two off in a game of 40k which as we all know represents an Epic Assault.
All that being said I'd honestly suggest this instead
Stormfang Gunship AV 30cm
F:5+,C:6+,A:4+
Hellfrost Destructor 30cm MW4+, Disrupt, FxF
Twin Lascannon 45cm AT4+, FxF
Bolters, (small arms) EA+1
Reinforced Armour, Skimmer
Now if you want to ignore all the above, groovy too. But in the stats in your post, that's a unit at least...350 points probably more EACH. It's effectively one shots EVERY.SINGLE.NON-WE.FLYER.IN.EA 50% of the time (more on intercept at 66%) so yeah... that's a wee bit much. Plus the over abundance of too long ranged AA coupled with the great ground attack so...
EDIT: I misread there being AA on the big cannon so ignore
So considering how valuable MW and disrupt are for an assault-centric marine army like wolves, with their above avg sized core formations with free commanders I'd suggest something like formations of 2 at ... 350?
If you want planetfall then add...25 points each?
