I was only able to complete a portion of “Behind Closed Doors” before starting and completing some of the second zone’s storyline, as the NPC finally showed up in the building after the speakeasy portion in the corridor section. However, both before and after starting the second zone, the citizen to start “Brotherhood in the Skolzgal Woods” wasn’t there.
Based on what was mentioned on Sojourner of Isle of Dorn Not Able to Be Completed - Support / Bug Report - World of Warcraft Forums (blizzard.com), it seems like some quests to complete the Sojourner lines are tied to the story and unlocks NPCs as you complete it, so the next part of BCD and BitSW, may probably open after I complete more of the second zone or after the full storyline is complete.