I’m thinking Arctyrant will be very problematic. It’s got Dragon Dance and a Fishious Rend clone with Strong Jaw, and it’s naturally faster and hits harder than Dracovish. After one Dragon Dance, it’s faster than Scarf Dracovish, stronger than Band Dracovish, and isn’t locked into a move. Also, unlike Electric and Water, Ice doesn’t have a type or Ability that’s immune to it, so you can’t switch in something like Seismitoad. The only things that can even hope to switch in on a Biting Chill at +1 or +2 are fully invested physically bulky dual-resists like Heatran, Bakufugu, Fojiyama and Reluvish (or Thick Fat Arctigoat, a physically bulky triple-resist). All of these either take a huge chunk from Earthquake or are outright OHKO’d by it, except for Levitate Bakufugu. Even at only +1, Life Orb Arctyrant’s Biting Chill can still 2HKO a fully invested Avalugg. Arctochomp is a bit easier to deal with due to the lack of Dragon Dance or Strong Jaw, but it’s still going to end up being OP.
I hate to propose a ban before any playtesting is done, but all evidence points to Biting Chill making two separate Pokémon broken, so banning the move is probably the best solution.
Autotomize on Reluvish is probably also a bit much, and it should lose Rock Polish as well, considering it has Fishious Rend, Strong Jaw, base 130 Attack, and a better offensive and defensive typing than Dracovish. Remember that the moves we’re working with here are ridiculously powerful and should be treated very carefully.