Indigan Praefects conversion help

So those converted regiments are pretty dang cool in the new Astra Militarum Codex and so I thought I'd try my hand at converting some Indigan Praefects. The model in the book is mostly Genestealer Neophyte with a Skitarii Vanguard helmet and Tempestus Scion backpack but I was wondering if anyone had any conversion ideas for units beyond just the infantry, command squads, officers etc.