Yup, i think the arc node is a bit much. If you want to take it as a jack rather than a node then that's very expensive, but if you casually like the miniature then go for it. The main reason for not taking it is that with both the raider captain and the necrosurgeon you could really begin to play skarre forward, rendering arc nodes extraneous. The shenanigans you could get up to with that added range are delicious
I have always wanted to play skarre with an arc node (as i play her quite defensively) to alpha strike after that first turn of ritual sacrifice. A few blood rain templates can absolutely wreck
It's all personal preference
Three stitch thralls aren't much to run on, and the necrosurgeon would struggle to survive without anything to pawn. Have you considered taking scrap thralls. At a third of a point per miniature they become very good fuel for her ritual sacrifice and strike. I would normally use ritual sacrifice each turn of the game (besides the first) this way you end up with an average of nine and a half focus (more than Haley2.) This is what makes Skarre one of the most versatile casters in Cryx. She can buff units with dark guidance, run mass jacks (with high focus,) spellsling like hell (on a good roll you could get three blood rain templates down, literally decimates heavy infantry forces,) and, of course, really wreck it in melee. But she goes through a lot of health and a lot of miniatures in the process
She really isn't in any way a sensible caster
Is the bokur going to be attached to Skarre or Gorman? You should propbably try both, although the latter is strictly offensive since Gorman has stealth anyway
Hope i helped, this definitely gave me some thought on caster synergies