I would keep the farseer in with the scorps with fortune, it effectivly gives them an armor save better than 2+, and given the amount of CC troops being used, i'm not sure a double flanking force would be a good idea, especially not with the scorps up the middle. With this force I'd initially split the force, 2 serpents on one side, one on the other, and then re-deploy the 3rd serpent first turn. This tends to throw off most opponents as suddenly an expected attack is coming on the other side of the board. Throw the wraithlord up on the middle or so, he'll attract alot of firepower, and put the reapers/guardians about 1/3 of the way down the board by the main flanking force. Deep strike isn't too much of a problem, as anyone with the guts to do so will be facing 2 reaper squads and a full squad of guardians, plus whatever firepower you can spare from your wraithlord (if he's still alive, expect him to die) and your serpents.
This will give you a well protected fire base and a powerful assault element, proceed to shoot the crap out of the flank, assault it, and then just roll on up. Oh, and you can't FoF the wraithlord mindwarp
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