So what's a Tzeentch Warlord to do?
Option 1: Ahriman - 230 pts
Level 4 Psy is nice, and 3 witchfire powers is neat if you can get the distance. Biomancy makes him survivable and a good AP4 killer but don't count on killing much more than that. The Infiltrating D3 is certainly one of the better Warlord traits for Chaos. However the biggest reason I'm liking him over the normal sorcerer is Fearless which is really wonderful to stick with cultists, terminators, or obliterators. All of which he can infiltrate with to create some pain for the other side which is awfully nice.
Option 2: Terminator Sorc, Lvl 3, Terminator Armor, Spell Familiar, MoT -165 pts
What you gain over Ahriman is a 2+ save and rerolls on Psy Tests, also you could go Force Axe which is certainly a bonus over a stupid staff.
What you lose is 1 Lvl Mastery, Fearless, Only one Witchfire Power per turn, the Auto Infiltrate trait, and slightly worse stats (-1 BS, -1 W, -1 I, -1 A).
Is that worth 65 points is the real question. It is a pretty tough call. Rerolling Psy test is really nice, but almost necessary on the 2 W sorc. Ahriman has that extra wound but it still sucks to roll perils, and as much as he is casting it is going to come up almost every game. The 2+ is really nice but that can also be offset by a (slightly) better chance at getting Biomancy powers that can really buff you. For me it really comes down to Fearless (which is great) and Infiltrate, which you can possibly get by rolling, or by taking Huron (see below).
If you want to spend even more points you can give him the Sigil to gain +1 Invul, but that is a lot of points to get that 3++ on a 2 W piece!
Option 3: Sorc, Lvl 1, MoT- 75 pts
So... this fulfills your need to unlock 1ksons. Beyond that he is pretty much just a challenge away from getting owned by just about anything. A 3+ 6++ HQ marine with 2 wounds is nothing more than filler, he's barely better than a normal Aspiring Sorcerer! You could certainly spend some points to beef him up but I'd probably build the rest of the army first and then sparingly add to this guy.
SO you need one of those kind of options to get the 1ksons unlocked. There are a few other flavors of Sorc you could do, but I think the roles can be better filled by Lords.
Option 4: Terminator Lord, MoT, PF- 130 Points
This guy is pretty cheap and can be plenty effective. You can stick him right in with Cultists, Termies, or Oblits and he makes them all better! He's pretty survivable but that area could be better if he could somehow get T5 but alas. You could put more points again for Sigil but that is a lot of points to just go from 4++ to 3++.
Option 5: Lord, MoT, Sigil, Disk, Murder Sword- 170
So this guy is T5 with 3+/3++ which is pretty dead sexy. The only drawback is he isn't 2+ which is a shame. This is probably the only time I would consider adding one of the Chaos Weapons to the Lord, and largely because of the Mobility he has with the jetbike. He has the easiest time hopping around to find that character that the Murder Sword is all antsy to Murder and that seems pretty cool. He can also avoid the 2+ save guys that he can't hurt which would be my fear giving the Murder Sword to a non mobile HQ. He's not TOO expensive but he isn't cheap either.
Option 6: Daemon Prince, Wings, Armor, Tzeentch, Black Mace- 265
So you want to spend a bunch of points on a crazy fast killing machine? This guy is the answer. He looks like a ton of fun, but he isn't without risk. One Str 10 wound or forceweapon and this guy is toast. Talk about risk!
I see these 6 options and in a large game I can see using 2 guys but the question is how many points do you want to spend on HQs? Oddly there are some natural parings that come down damn close point wise.
Option 1 & 4 = 360
Option 2 & 5 = 335
Option 3 & 6 = 340
Of course you could go multiple different ways on this, but it is hard to figure out how to build an effective army behind Ahriman and the Daemon prince as that is almost 500 points!
Obviously in smaller games comprimises are going to need to be met, and even 1750-1850 335-360 pts in HQs is no small thing. So the question of 2 Hqs might be out altogether if we find we can't get enough bodies or guns on the ground!
More games are most defintely needed to see how these options play out with the new book.
Oh and I forgot another possible option is Huron. For 160 points he's a steal of a Lord with a bit of Psy in there as well. He'd be easy to make a fluffy Tzeentch Lord stand in I think. Decent at CC, Infiltrate Trait, Fearless, he has the goods to be nice. I just don't know if I prefer him over the Termie lord or Disc Lord...