If their attack and defensive stats are good enough, they could be good revenge killers on bulky offense teams, especially in Hail.
How often are bulky offense teams in Hail? Seems strange to pick Slush Rush without planning to be under Hail regularly. Competes with Beartic for a Slush Rush spot. (Confirmed them in the trailer.) How would you make them different without making Beartic irrelevant?
Beartic's base stats: 95 HP / 130 Atk / 80 Def / 70 SpAtk / 80 SpDef / 50 Speed
Cannot see it going any faster than Beartic. Shies away from going slower, however. Practically turns Slush Rush into a trap that way. Perhaps something more like:
Cetitan theoretical 1: 80 HP / 130 Atk / 135 Def / 50 SpAtk / 60 SpDef / 50 Speed
Specializes it more towards withstanding physical hits. Could also give it a unique move and drop its Attack slightly. Imagine this with an Ice-type Power-Up Punch or physical Ice Eruption.
Alternatively, focus on a Thick Fat build. Looks to Mamoswine (another Thick Fat Pokemon). Tries not to step on its toes.
Mamoswine's base stats: 110 HP / 130 Atk / 80 Def / 70 SpAtk / 60 SpDef / 80 Speed
(Actually made the previous theoretical relatively close to Mamoswine.) Works with a few more points this time. Locks Speed back in at 50. Would rather tank Speed more for Trick Room, but oh well. Envisions an Assault Vest spread. So,
Cetitan theoretical 2: 120 HP / 120 Atk / 120 Def / 50 SpAtk / 70 SpDef / 50 Speed
Could see this working okay. Asks for an Ice Drain Punch for sure. Balanced out its stats more than Avalugg's. Doubts
too many super-effective special attacks not covered by Thick Fat. Lacks way more power than, say, Conkeldurr, however. Risks eating a second attack.