[spoiler]With Immunity and without his backup, and if Spell Defense decreases AoE spell hits to cause scatter... Of course, the GM didn't let us use a Spirit's Concealment and said Auslander and co. had taken Perception tests in advance so it didn't matter I was sneaking in the bushes at their +3 instead of -2. With a much tougher encounter, I imagine he'd have given us more chances to prepare proper defenses, his inexperience with Missions GMing was partially at play here. Oh, and he forgot that where we took -3 from Heavy Fog with Thermographic Vision, the Shedim would have been at -6. Whups. ^_^' He did mention that as Missions complaint: No clear description of what level the modifiers are on.
With my sniper hidden in the bushes I'd have shot Auslander half to death, even if both of us used Edge on that first shot. If you also do not give him a full 8 Edge but, like Spirits, 4 instead, he'd get drained faster. So that makes it decently survivable, though very tough.
Of course the next point of debate is how many Shedim you face in advance, since those soften up the players. GM went "you guys are taking too long, roll Sneaking" and bam, it'd have been easier if we'd had managed that more sneaky, especially when taking potshots in advance.
Let's see... Auslander isn't taking a Simple Perception action at first and focusing on those in the clearing, so that'd be a -2. Give him a -6 from the fog and we're talking 8 perception dice vs 15 sneaking dice, bam. And that's without Concealment. So a sneaky sniper potshot is an option. Roll 12 dice after vision penalties, reroll for ~7 hits, 12P/-8 +7 = 19P/-8. 8 Body + Immunity 16-8=16 dice + 4 autohits, edge it with a reroll for 9 hits: 6 damage taken. And just like that he's halfway gone. But without that, oh boy... The clearing is what, 30m radius? A Force 8 Toxic Wave likely hits most in the clearing.
Now I want to do this fight properly with Immunity from Possession, a dozen Shedim vs 6 players, and let the players be smart and plan tactics, rather than getting caught flatfooted because they suddenly have to roll Sneaking even when one character can't sneak.[/spoiler]