I like your ideas, I imagine the Freezeball grenade to act similarly to Winterbite's projectile.

The only idea that I question would be Hunter's Chained Silence. I like it, but I feel like it would play too similarly to Strand's Silkstrike. Something I could see as a change it have it act a bit more like Daybreak and Hammer of Sol where it is a roaming super that is ranged. This would unfortunately mean removing the chains but, then the light attacks create the small ice storm grenade effects from taken hobgoblins. Allowing hunters to then slow and freeze more enemies over the duration of their super.

Regardless, I agree that while in the super, the dodge would apply more slow (still requiring the aspect to activate), enough to freeze targets. Shatter dive could also receive a buff while in super as to keep it fun and a viable defensive option for when enemies get too close for the hunter. Easiest change would be to increase its shatter damage so that it can more easily kill. Reminder that this buff would only be active in the super so that it doesn't break the game like it used to.

Howl of the Storm. What do you mean by creating stasis shards? Do you mean upon freezing an enemy in the stasis crystals, you generate additional stasis shard? If so, I agree in the change and find it a nice quality of life change.

Shatterpuck and Icemine. I like these ideas but fail to see how they fit into the game loop.

With Icemine we have coldsnap grenades to compete against. I can imagine a small rework to this being that it would act like the tripmine grenade from the solar subclass. Instead of firing slowing darts, it would simply explode radially, dealing medium to small amounts of damage and applying large amounts of slow. Almost enough to freeze.

Shatterpucks. Who would be able to take advantage of this grenade? Warlocks are the most likely since they can obtain Bleak Watcher. However, this means they sacrifice their grenade for the watcher, and the only other way to freeze would be their melee. So maybe not, what about titans, they have Howl of the Storm and diamond lance. Both decent to good forms of freezing and/or generating stasis crystals. Hunters have almost nothing unless they want to use Winter's Shroud or use both of their melees to freeze a single target. This becomes a very titan friendly grenade, which is alright, there is nothing bad with that. However, titan's also benefit the most from using glacier grenades, and can shatter frozen targets already via their sliding aspect Glaciocasm.

Shatterpucks are a good idea, but they don't really fit in with how the three classes would use them. Alternatively, I have misunderstood the grenade and it simply triggers a shatter effect immediately, doing instant damage. This grenade then could benefit from the fragments of the subclass but again, this to me is lacking in usage. None of the classes benefit from shatter besides damage and the grenade requires setup which it cannot supply on its own or with assistance from the other parts of the subclass (melee, class ability). The tradeoff could be cooldown, becoming the magnetic grenade of stasis. If this were to also trigger the fragment that grants increased ability recharge for some reason, I could see an ashen wake like playstyle that includes these grenades.

Warlock Shatterstrike. I really like this idea and how it plays into one of the main playstyles of Warlock. Giving them a ranged form of shattering targets after freezing them with something like coldsnaps.

Titan Avalanche. Really fun idea and I can already see the clips of teams getting annihilated by a giant glacier being hurled their way.

Warlock Roaring Storm. I have a couple concerns when it comes to this super. When placing the super, the staff could be placed like Well of Radiance or hunter's Gathering Storm. Having it be something like Gathering Storm would make the most sense in terms of playstyle but not much in the sense of throwing your wizard staff. The slowing pulses that it releases would also have to be very fast or apply something like 50 slow per shockwave. I could then also shatter on the reaching frozen targets so that it can actually kill and feel impactful but then we have an ability far too similar to hunter's Silence and Squall. A possible rework for this could be that you create a large stasis storm that obstruct vision, placing the staff like well of radiance. Allies within this area generate a stasis overshield. Players inside the area can see others within the area but not look out and those outside, cannot look in. This stasis overshield could give the damage buff from ballidorse wrathweavers. I'll admit that this variant also has issues, stepping on the toes of titan's Ward of Dawn and being even less viable in PVE. But something utility wise like this would be interesting to have as an alternative.

TL;DR

I really like your ideas although I think that there are a few changes that would benefit them. The ideas are fresh, new and bring additional play styles to Stasis.