As the unit needs to participate in one combat before the Smoke takes effect, they are best utilized on units that initiate first and/or intend to take multiple enemies on in one turn. As such, they are most valuable on maps with a lot of enemies, especially Abyssals
At a glance I think Zeke and Duo Dagr are the strongest choices of these units. Zeke’s play style naturally leans towards tanking and being able to block follow ups with Atk Smoke 4 while making forced follow ups of his own is very powerful. Also you are running a Stance over a Catch, so the Menace is a lot less useful for Zeke.
Duo Dagr is one of the better choices for Spd Smoke 4 being a rare flier with NFU and having pretty solid bulk, especially with the build you’re running.
The others I think are mostly fine as is. Myrrh already blocks follow ups with her Prf and has respectable but not super high Spd so she doesn’t gain much from Dodge or additional follow up blocking. Altina does gain a fair bit from Atk Smoke 4 but she also has her button to give her Vantage; no point in blocking follow ups if she kills her foe before they can hit her. And Nótt really likes the visible buffs she gains from her Menace for her Bonus Doubler Prf; Atk Smoke 4 can be interesting for her though after one combat