Most wiki information about faction hits are wrong sadly, and I have no idea if the current values are correct for the monsters you are talking about. From my understanding, the majority of monsters only give 1 or 2 faction per kill, which is why that is typically the slowest way to go.
Some monsters are well documented at giving more faction per kill (such as Velious City Leaders), but those mobs are easy to document since they are killed so often, and it is easy to see the large jump in faction.
As a Troll I wouldn't worry about raising faction in good cities, especially Highpass, where you don't need to buy any spells for Shadowknight/Shaman. With a bit more game knowledge evil races can find enough places to vendor. I mostly play a Troll or Ogre, and I have little issue with vendoring, banking, etc.
If you are dead set on improving your faction, I believe
https://wiki.project1999.com/Orc_Scalp_Collecting is the way to go for highpass. But since I assume you are still KoS, you will probably need to ask a druid to wolf form you first before doing the quest turn in.