GW has just released an FAQ for the current IG Codex. Most seems like common sense to me. It can be found here
DeathStrike hits all vehicles within radius at full strength (no center hole) (well duh).
No, you can't carry GK Termies in Valks
No, you can't use a mortar in your CCS to spot for the MoO
Yes, Platoon Commander SC's (Al'Rahem, Chenkov) can be inducted for WH, DH armies
No, Advisor (Fleet Off, Astropath) bonuses don't stack.