For every 3-shot weapon, you break the rule once, so a unit of 5 Stealths would break the rule 5 times.
I have yet to try it, but I have made a team with only 2 Stealths, and the rest are Pathfinders (I was allowed to use them without breaking the Immutable law since Markerlights are COMEPLETELY useless in Kill Team). I figured that with Ork Fighter, the Shas'vre has WS and I 4. since the entire team has Assault Weapons, then I can shoot and charge into the Brute squad (only causing 1 Klaxon, since one you shoot the Brutes become Aware). And if I GET charged, The Pathfinders have Photon Grenades, so I don't need to worry. And also, in the event that all but the Shas'vre are dead, the Shas'vre could use the Jet Pack in a last-ditch effort to try to complete the objective. With Camo Gear, I think it might work. It only breaks 3 Mutable laws (2 3-shot weapons and 2 squads).
Good luck with your team. Stealth Suits are appearently quite effective in Kill Team.