Does anyone know who these are, and if we'll ever see them online? I keep seeing glimpses of some piece of art with a Khorne Terminator and I'd kill for it, and just happen to love pre-gens.

I doubt the character stats will be published, as they are, well, exclusive to the Collector's Edition.

However, for a quick overview:

The Champion Areus Ekoriatus comes from an unknown legion (he has even forgotten whether it was a loyalist or traitor one). He defected to Chaos when he felt he couldn't gain the recognition that was due to him while overshadowed by the Emperor, then defected from Horus because of the same reason. And when a chaotic oracle prophesied that he would need the support of a chaos god, he killed the oracle and denounced the gods.
Yup, this guy has a bit of an ego problem. Funnily enough, the advanced version provided has the Mark of Slaanesh - it appears the Dark Prince found his arrogance amusing enough to not care that Areus doesn't actually worship him.

The Chosen Xhoric the blood-bathed (formerly Brother-Captain Xhoric) has a relatively cliche story of being the Space Marine who enjoyed slaughter just a little too much until a campaign against Chaos had him go berserk and kill both sides. Now he's fused to his Tactical Dreadnought armour…

The Forsaken Toran Ghul is another ex-loyalist who, during an assault on a Craftworld, killed AdMech adepts to obtain their virus warheads with which he managed to obtain victory. His chapter was forced to turn him over to the AdMech, he fled from a show-trial on Mars. Considering the AdMech a mere symptom of the disease of stagnance that plagues the Imperium, he's determined to bring it down so a new humanity may create something better.

Akhor'Menet of the Thousand Sons, the Sorcerer, is… well, a Thousand Sons guy who's a little pissed at the whole Rubric debacle and strives to either rescue or lay to rest his dusty comrades.

Apostate Artoria Pellaco was conceived by Slaanesh cultist nobles in a ritual, then locked away for her entire childhood. After being secretly tutored by a probably daemonic creature, she killed both her parents and their cult before setting out on the usual crusade, mostly rallying mutants and underhivers to her banner.

Helia Vulka, the Heretek, has mostly the same ambitions as the Broken Chains heretek: Graft daemonic flesh to human to perfect the human form. It also had about the same impression on her fellow Magoi.

Rictor Kaeso is the sample Renegade, a former guardsman Medic who became cold to the plight of suffering around him. When the ship transporting his regiment back to Scintilla fell to a plague, he was the only survivor and as such embraced father Nurgle before the warp-tides brought the ghost ship to the Vortex.

Farzuk Nim'Zahfar the Psyker is a feral worlder who uses the severed head of his best friend who protected him against a predatory animal as his psy-focus. After returning from that experience to his native village, the other villagers were less-than-understanding, so he used his powers again, triggered massive perils and ripped a hole into reality that sent him to the Vortex.

(That being said, it would have been nice if the extra 16 pages didn't rip all the page references in the books to shreds because those weren't updated to account for them…)

Whoa, those are some really cool concepts…

****! I'd love to see Xhoric's art. Let's hope somehow these sneak out onto the wider net, or have their assets reused.

Additionally, all characters have something unique.
The Champion has his armour which penalizes every sentient non-daemonic being with a -20 to melee attacks (may I say "OUCH!"?) as all the reflections of his enemies are twisted into his own.
The Chosen has the Tusked Armour, a termie suit with horns (well, mammoth-like tusks), a combi-bolter/flamer and a chainfist.
The Forsaken gets the Flail of Vengeance,a multiheaded flail (text says seven, picture goes for a more sensible three) made from the skulls of slain Magoi whom he didn't want to be made into servo-skulls - it's not Toxic, merely Crippling, Devastating, Flexible, Unbalanced and Power Fielded (again, ouch!).
The Sorcerer has got a Jar of Dirt - no, it's actually a Bag of Dust which may or may not be from his dusted battlebrothers, but certainly improves the Penetration of a bolt weapon when it's sprinkled upon it.
The Apostate get's her signature mutation, the Nest of Vipers - essentially medusa-esque hair consisting of barbed and poisonous tentacles which she can use (badly) in combat. As far as the unique traits of the others go, hers is kinda meh .
The Heretek has her daemonic grafts which grant her attribute bonuses and can be overtaxed, trading some intelligence for a d5 of a corporeal attribute.
The Renegade starts play with the Mortis Kit, an upgraded medicae kit that improves First Aid a little and facilitates drug creation by letting him Acquire them with Trade(Chymist) rather than Infamy.
And finally the Psyker would never leave town without his buddy's head. It's a psy-focus that also lessens psychic phenomena.

There's some incredibly good stuff in there (like the two armours), some that is rather disappointing and some that's alright.

Looks like a fairly interesting set of characters were given away. A shame if they did turn the page reference to hell.

Rictor Kaeso is the sample Renegade, a former guardsman Medic who became cold to the plight of suffering around him. When the ship transporting his regiment back to Scintilla fell to a plague, he was the only survivor and as such embraced father Nurgle before the warp-tides brought the ghost ship to the Vortex.

Now how is normally created character supposed to compare to pre-gens? It would be fun to have some rules for creating such stuff that you can get at creation only (and meaby through cursed heirdoom).
Also has anyone checked whether these characters are done right? Because preview of heretek was availible here and I think there were some errors in stats.

Now how is normally created character supposed to compare to pre-gens? It would be fun to have some rules for creating such stuff that you can get at creation only (and meaby through cursed heirdoom).

Um… ask your GM? The point of these addons is that they're tailormade for the character in question. I don't think any rule could provide that.

I would love to see those item stats. Anybody got them?