Dark Elf illusion would be most likely to get you the best faction at the outpost. They hate Iksar, and I'm not sure on Troll/Ogres, but iirc, Dark Elves have the highest base faction with Venril Sathir. (Odd, since VS is an Iksar, that they'd be KoS, but hey...)
In any case, I'd highly suggest farming the ******** out of the snark braids before you do any potion/charm/alliance/etc stuff. Get a whole load of the braids, slap on the illusion, and turn them in 4 at a time to Captain Rottgrime for a faction boost. It takes a lot to do. My main was a dark elf, and he started apprehensive or dubi to the outpost. I spent my entire span from 26-43 or so in the Overthere. Granted, I had to share braids with people once in a while, but for the most part I got them. And at the end of it all, I still ended up only Dubious. And now, after working on my epic, concussion quest, Veeshan's Peak key, etc, I'm down to apprehensive again. Believe me, the faction falls about 100x faster than it rises.
Chances are, if you're KoS to OT already, your only hope in hell will be to get a half-decent puller and charmer. Pull Rottgrime out of the outpost, add-free if possible, then charm and hand in a buncha braids.
Not sure if you can get someone to charm the undead foreman for the hammer turnin or not, since I think he'd only be indifferent to you. I don't know much about charm.