I've gvot a kill team tournament at my club tomorrow, was also thinking about using scourges, I wouldn't be a huge fan of the mandrakes as backup, but not sure what else you could get that would be decent for the points you have left, certainly the scourges will be doing your heavy lifting.
I've used bikes in kill team before, though it was under the previous codex and they were awesome - the old bladevane rules frustrated the hell out of the Tau player who brought crisis suits, he couldn't get close enough to do any real damage and I just buzzed over him every turn waiting for him to fail his saves. Did quite well in that one until I came up against a guy who'd figured out my strategy and just sat all his models back up in a corner of the board so I couldn't fly over him.
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