Specific to unlocking the Helnim thieves guild,
TR_m2_Hofmund has two greetings7 which have critical results, and should be recreated at least in greeting 5 instead (to not be overwritten by generic faction greetings 6),

"So Valtio sent you, eh? Well, if you're looking for jobs or advancement, I'm the one you'll be wanting to speak to."
"So Valtio sent you, eh? You'll be looking to join the Thieves Guild then, I suppose."

moved to greeting 1