I do think that a backfield wrack with a hexrifle might not be bad in Kill Team. Unfortunately, they can't take the sniper specialist, so that affects their usefulness somewhat.
The ossefactor isn't a bad choice, with a 2" 'explosion' radius around any target that you take out with it.
For some reason, they removed the spiritseer's witchstaff ability to always wound on 2's.
Mandrakes might be an auto-take, with their 'deepstrike up to 3 mandrakes no closer than 5" of enemy models ability', particularly since their shooting is not bad.