Guess what? Another Gespenst concept!

My previous approach was more defensive, but now I've been going a little more straight forward that happens to make Canas more offensive, but can totally work defensively.

Base effect is +5 spd and a slaying effect. We haven't seen a flat +5 stat buff since Audhuluma and frankly Canas could use it to make something of his mediocre 29 spd; they didn't absolutely dump it so we may as well build off it. The slaying effect is just a niceity, more Icebergs is nice and helps his kinda ok atk. These two stats alone make Canas into a decently effective Offensive Support unit since he can build off his spd further with skills like Fury or Atk/Spd bond and he still ploys well, and his low defense now becomes more negligible since he now can effective be more offensive and just use Desperation.

Refine effect is equally simple and very practical: Spd Ploy. 34 spd with the base effect, 37 with Fury, and with the ploy he can double anyone who has 42 spd, before he himself is buffed of course.
So I pretty much made Canas into a more offensively viable Arvis, or more like a Red Lute with no IVs. Really though the refine effect could be plenty of other things, I mostly just really think he should get those base effects. I just went for something easy and not so gimmicky like one of those specific bond effects (admittedly the exact bond effect Merric and Linde have would help him out a lot too)