Orphic this is going to need some work with Spiritomb gone. Be sure to remove all mentions of it.
I also highly doubt the viability of both Scarf and Assault Vest. Scarf is really easy to counter because it's weak and the reason why Malamar is scary is because it has coverage for Fighting resists that come in on Superpower. The only real niche would be Scarf Popsy Turvy, which isn't even on the set. I guess Assault Vest could be usable, but I still don't think it's the best Malamar can do.
I'd like to see discussion of a RestTalk set, a la:
Malamar @ Leftovers
Ability: Contrary
248 HP / 8 Def / 252 SpD
Careful Nature
- Rest
- Sleep Talk
- Superpower
- Night Slash
Effectively, it's a RestTalk Bulk Up set but with good coverage. The only thing the set struggles with is Fairy-types, which every Malamar struggles to beat anyways.
I don't think ChestoRest is the best either because Knock Off effectively makes it worthless. This set doesn't mind Knock Off and boosts more reliably, exchanging immediate offensive pressure for the ability to butt devastate stall and balanced teams.