I have had great success against tau. My tactic is to bring grots and wracks and shove them in his face turn one. All the while withering them down with venom fire. And always go for their pathfinders first. Send the grots and wracks to his scoring troops, usually great becuz they have them clumped together for supporting fire. Grots soak up almost all of their fire. Tau need stuff to shoot at so diversions work really well against them.
On your list I would get rid of drahzar. Bring a haemy or two. Bring stationary splinterborn (I usually do 3- 2 splinter cannons and 1 dark lance). I bring 2 of these at a regular FOC.
I think the incubi are a waste of points. They are WAY to Killy for tau. You really don't want to be left out in the open with tau. I would put your warriors in 5 man squads in venoms. For a few reason, 1 gives more scoring units, 2 gives target saturation, 3 venoms are amazing. And I would recommend putting caltrops on your reavers. I usually designate them to either be AT or AI. And I have found them to be more effective AI. Personal preference though. But for sure get rid of the incubi and drahzar. And definitely bring more venoms dude.
"... get me the holy hand grenade!!!! .... 1..2.....5, 3 SIR 3!!!!"