The good news is, is sounds like your opponent doesn't field the scariest chaos combos he could. He has a lot of bodies, and you say he's probably bringing some IG support. If you expect a lot of bodies on the table at a time, consider a razorwing or even two to help clear them off. If you don't already, consider running your haemonculus and a talos and cronos as part of that Covens formation that lets you mix the 3 together. Give the haemonculus a webway portal, land on his doorstep, and proceed to show him what a squad of MCs does to non-fearless units. Also a good answer to his vehicles once you clear a path.
If you expect lots of vehicles, I'm afraid the options you've listed aren't great for dealing with them. Your warrior squads can pack blasters and sybarite haywire grenades, and your raiders can take lances, but the former require you get pretty close, and the latter just aren't all that reliable. Scourges are my main go to when I really need AT, but it looks like that isn't an option for you. I'm not sure it would really help, but you could maybe create a blasterborn squad out of your warriors. Your reavers are actually pretty well equipped for dealing with vehicles, but a gunline will typically be very scary for them to deal with. Consider starting the reavers on the table behind terrain, start moving them up turn 2 as all your deepstrikers arrive (the haemonculus formation and maybe your raiders), then have them start mixing it up with targets of opportunity on turn 3 when that haemonculus squad is good to assault!
Your incubi are great against marines. Bring them. Grotesques are cool, but you'll need to figure out how your transporting them if you take them. I suggest an archon with a webway portal. I'm not a huge fan of wracks Now that they aren't troops, but they aren't bad. Maybe you can use them with Urien as part of a coven formation or something?
I think your best bet, depending on how many vehicles he brings, is to hide whatever starts on the board (reavers probably) behind a building, then go for a deepstrike beta strike. Use your warriors to try and clear out priority targets screening the vehicles with their poison, use your raiders (I'm assuming they have lances) to try and shut down the scariest enemy vehicle, shut down his infantry shooting turn 3 by assaulting with your incubi, grotesques, and monster squad, and then basically just carve your way towards his vehicles with the grots and monsters. Reavers too, if they can make it.